
188 P.3d 354 (2008)
220 Or. App. 542
DeLEON, INC., Petitioner,
v.
DEPARTMENT OF HUMAN SERVICES, Respondent.
A132259.
Court of Appeals of Oregon.
Argued and Submitted December 20, 2007.
Decided June 18, 2008.
*355 Jack Oswald argued the cause and filed the briefs for petitioner.
Michael C. Livingston, Senior Assistant Attorney General, argued the cause for respondent. With him on the brief were Hardy Myers, Attorney General, and Mary H. Williams, Solicitor General.
Before LANDAU, Presiding Judge, and SCHUMAN, Judge, and ORTEGA, Judge.
SCHUMAN, J.
The Department of Human Services (DHS) penalized petitioner DeLeon, Inc., the owner and operator of a grocery store, for violating rules governing the federally sponsored Women, Infants, and Children (WIC) Program. Petitioner seeks judicial review, arguing that DHS incorrectly construed and applied the rules. We agree with petitioner. We therefore reverse and remand.
The WIC Program provides nutrition education and counseling, nutritious supplemental foods, and health screening and referral services for infants, children in certain high-risk categories, and pregnant and breast-feeding women. ORS 409.600; OAR XXX-XXX-XXXX(1).[1] As relevant to this case, the program provides participants with "food instruments," which are vouchers on which a specific quantity of a particular authorized product is listed (for example, "Five cans 12.9 oz. Enfamil Lipil with Iron Powder"). See OAR XXX-XXX-XXXX(13) (defining "food instruments"). The participant typically takes the voucher to a store that is an authorized vendor and uses it to "pay for" the listed product; the shopper signs the voucher and gives it to the store cashier instead of money, a check, or a credit card. The store, in turn, fills in a box on the voucher specifying how much the product would have cost a non-WIC shopper, sends the voucher to DHS, and receives reimbursement.
Federal rules require that, in order to continue receiving federal funds to participate in the program, a state must adopt and implement standards and procedures of administration. 7 CFR Part 246; OAR XXX-XXX-XXXX(2). One such procedure is mandatory monitoring of WIC vendors by the state through "compliance buys," that is, "covert, on-site investigation[s] in which a representative of the [state] Program poses as a participant, parent or caretaker of an infant or child participant, or proxy, transacts one or more food instruments, and does not reveal during the visit that he or she is a program representative." 7 CFR § 246.2.
The WIC Program in Oregon is administered by DHS. OAR XXX-XXX-XXXX(3). Under ORS 409.600(2), DHS is required to adopt "[s]tandards and procedures to guide administration of the [WIC P]rogram by the state in conformity with federal requirements and to define the rights, responsibilities, and legal procedures of program vendors." Accordingly, DHS has promulgated rules, violations of which are classified as Type 1, 2, or 3, based on severity. OAR XXX-XXX-XXXX. As required by federal law, the agency has also adopted rules for "compliance buys." OAR XXX-XXX-XXXX(8).
In the present case, petitioner seeks review of DHS's order finding two Type 3 *356 violations, the penalty for each of which, if upheld, is petitioner's disqualification as a WIC provider for a period of three years. Each violation, in turn, involves a "pattern" of offenses, that is, "three or more of the same rule violation that occurs within a single investigation." OAR XXX-XXX-XXXX(18). DHS charged petitioner with, first, engaging in a "pattern of vendor overcharges." OAR XXX-XXX-XXXX(3)(b)(C). A "vendor overcharge" occurs when a vendor "intentionally or unintentionally charg[es] DHS more for authorized foods than the actual shelf price or the price they charge other shoppers." OAR XXX-XXX-XXXX(28). Second, DHS charged petitioner with "a pattern of charging for authorized foods not received by the authorized shopper." OAR XXX-XXX-XXXX(3)(b)(E). "Authorized food[s]" are "any supplemental foods listed on the WIC Authorized Food List or the food instrument," OAR XXX-XXX-XXXX(4), and an "authorized shopper" is a "participant or any person designated by a participant who has been documented as such at the local agency to act on the participant's behalf and, in the case of an infant or child, the caretaker or the caretaker's designee." OAR XXX-XXX-XXXX(5). OAR XXX-XXX-XXXX(17) defines "participant" as "any pregnant woman, breastfeeding woman, post-partum woman, infant or child who receives authorized foods or food instruments under the WIC Program, and the breast-fed infant of any participating breastfeeding woman."
In sum, according to DHS, on three occasions, petitioner sought reimbursement from DHS for the sale of an authorized food, in an amount greater than the shelf price of that food; and, on three occasions, petitioner sought reimbursement from DHS for an authorized food not received by the authorized shopper.
Petitioner does not dispute DHS's account of the events leading to the charges. Petitioner entered into a vendor agreement with DHS on September 25, 2002, under which petitioner was authorized to sell food items in return for Oregon WIC food instruments. In the vendor agreement, petitioner agreed to "write the actual purchase price in the designated box on the food instrument before the authorized shopper signs the food instrument." The agreement also provided, "The vendor shall be accountable for any intentional or unintentional action of its owners, officers, managers, employees or agents, with or without the knowledge of management, who violate the vendor agreement or federal or state statutes, regulations, policies or procedures governing the Program."
Sorenson is a DHS employee whose job duties include posing as an authorized shopper to conduct "compliance buys" as required under OAR XXX-XXX-XXXX(8). Sorenson is not a participant in the program, a designee of such a participant, or the caretaker of an infant or child who is a participant; in other words, he is not an "authorized shopper."
On July 1, 2005, Sorenson purchased from petitioner two cans of Similac, an infant formula, presenting a food instrument authorizing purchase of up to five cans of Enfamil, also an infant formula. Similac is not an authorized food; Enfamil is. Although the listed price of Similac was $12.99 per can for a total purchase price that should have been $25.98, petitioner wrote "$84.95" in the box indicating how much the purchased product sold for and redeemed the food instrument for that full amount from DHS.
On August 1, 2005, Sorenson purchased three cans of Enfamil from petitioner. The food instrument allowed for the purchase of up to five cans. Although the total shelf price for the three cans that Sorenson purchased was $50.97, petitioner redeemed the food instrument for $84.95, the price of five cans.
On August 24, 2005, Sorenson purchased three cans of Enfamil from petitioner. Again, although the total shelf price for the food items actually purchased was $50.97, petitioner redeemed the food instrument for $84.95, the price of five cans.
DHS initiated the present case by sending petitioner a notice of proposed termination of the vendor agreement. The notice asserted that petitioner (1) committed a pattern of vendor overcharges, in violation of OAR XXX-XXX-XXXX(3)(b)(C), and (2) committed a pattern of charging for authorized food not received by the authorized shopper, in violation *357 of OAR XXX-XXX-XXXX(3)(b)(E). An administrative law judge concluded in a proposed final order that petitioner's actions amounted to a pattern of vendor overcharges but not a pattern of charging for authorized foods not received by the authorized shopper. In its final order, DHS found that petitioner had engaged in a pattern of vendor overcharges and a pattern of charging for authorized foods not received by the authorized shopper. Either violation would suffice to justify the three-year disqualification imposed. Petitioner seeks judicial review.
Petitioner contends that DHS erroneously interpreted OAR XXX-XXX-XXXX(3)(b)(C) by ignoring its plain meaning. The rule provides that a "vendor overcharge" is "intentionally or unintentionally charging DHS more for authorized foods than the actual shelf price or the price they charge other shoppers." OAR XXX-XXX-XXXX(28) (emphasis added). According to petitioner, the July 1, 2005, purchase of Similacnot an authorized foodcannot serve as the basis for a violation of the rule. Without the July 1, 2005, vendor overcharge, only two overcharges occurred, so there is no "pattern."
DHS responds that OAR XXX-XXX-XXXX(3)(b)(C) and OAR XXX-XXX-XXXX(28) can plausibly be interpreted to cover the situation in this case. According to DHS, the definition of "vendor overcharge" can be paraphrased as follows: a "vendor overcharge" is "intentionally or unintentionally charging DHS more for authorized foods than the actual shelf price of the authorized foods that the buyer purchased or the price they charge other shoppers."[2] Petitioner charged DHS for five cans of Enfamil, an authorized food. The actual shelf price of the authorized food that Sorenson purchased was therefore zero. Thus, according to DHS, petitioner violated the rule.
An agency may determine whether the standard established in a rule has been met in a particular instance by interpreting the rule in the course of applying it. Papas v. OLCC, 213 Or.App. 369, 377, 161 P.3d 948 (2007); Goin v. Employment Dept., 203 Or. App. 758, 763-64, 126 P.3d 734 (2006). We defer to the agency's plausible interpretation of its own rule, including an interpretation made in the course of applying the rule, if that interpretation is not inconsistent with the wording of the rule, its context, or any other source of law. Don't Waste Oregon Com. v. Energy Facility Siting, 320 Or. 132, 142, 881 P.2d 119 (1994); Papas, 213 Or.App. at 377, 161 P.3d 948; Goin, 203 Or.App. at 763-64, 126 P.3d 734.
Petitioner argues that, because the violation included charging DHS for unauthorized food and two different administrative rules[3] speak more directly to that offense and impose only one-year disqualifications this administrative rule must be construed to avoid duplication. However, DHS may exercise its discretion in choosing the most appropriate rule violation charges to bring against a noncompliant vendor. At best, petitioner's argument suggests an alternative, plausible construction of the DHS rule. And it is settled law that a petitioner's plausible alternative construction of an agency rule does not mean that the agency's own construction is implausible. Oregon Restaurant Services v. Oregon State Lottery, 199 Or. App. 545, 562, 112 P.3d 398, rev. den., 339 Or. 406, 122 P.3d 64 (2005); Purdue Pharma, L.P. v. Dept. of Human Services., 199 Or. App. 199, 209, 110 P.3d 657, rev. den., 339 Or. 156, 119 P.3d 224 (2005).
*358 However, in the present case, the agency's construction is implausible; it cannot be reconciled with the plain language of the rule. The rule presupposes the purchase of authorized food, and that did not occur here. Contrary to DHS's theory, nothing in the rule justifies an interpretation that ties the "actual shelf price" to the price paid by a specific purchaser. "Actual" denotes an objective standard. The "actual" price of a can of infant formula is the price that exists according to some empirically verifiable measurement unassociated with any particular purchaser. See Webster's Third New Int'l Dictionary 22 (unabridged ed. 2002) ("actual" means "existing in fact or reality"). We therefore conclude that, although petitioner may well have violated some other rule, it did not violate OAR XXX-XXX-XXXX(3)(b)(c) by charging DHS for five cans of Enfamil when the purchaser bought two cans of Similac.
The agency's interpretation of OAR XXX-XXX-XXXX(3)(b)(E) presents a similar problem. That rule, as noted above, prohibits vendors from charging DHS for "authorized foods not received by the authorized shopper." Petitioner paraphrases the rule as prohibiting a merchant from overcharging DHS with respect to an authorized shopper's purchase. In other words, according to petitioner, the universe of purchases that can potentially result in violations includes only those in which the purchaser is an authorized shopper, and no such purchase occurred here. The state responds that we must read the rules in context. The WIC Program is a federally funded program, and federal law governing state participation requires "a representative of the [state] Program" to monitor vendors through compliance buys. 7 CFR § 246.2. Further, Oregon law requires DHS to adopt standards and procedures in order to stay in conformity with federal requirements. ORS 409.600(2). Pursuant to that mandate, DHS has adopted rules authorizing compliance buys through OAR XXX-XXX-XXXX[4] and OAR XXX-XXX-XXXX(8).[5] The state contends that, because these rules authorize the representative to "transact" a WIC food instrument, DHS reasonably construes its rules authorizing compliance buys to have the effect of either (1) amending OAR XXX-XXX-XXXX(3)(b)(E) and OAR XXX-XXX-XXXX(5) to include state representatives engaged in such transactions in the category of "authorized shoppers"; or (2) creating an exception to the limitation.
As stated previously, we defer to the agency's plausible interpretation of its own rule, including an interpretation made in the course of applying the rule, if that interpretation is not inconsistent with the wording of the rule, its context, or any other source of law. Don't Waste Oregon Com., 320 Or. at 142, 881 P.2d 119; Papas, 213 Or.App. at 377, 161 P.3d 948; Goin, 203 Or.App. at 763-64, 126 P.3d 734. In determining that petitioner violated OAR XXX-XXX-XXXX(3)(b)(E), DHS interpreted the rule to mean that an "authorized shopper" includes a DHS representative posing as a participant or a participant's designee. That "interpretation" cannot be reconciled with the text of the rule itself. To reiterate, OAR XXX-XXX-XXXX(5) defines "authorized shopper" to mean "the [WIC Program] participant or any person designated by a participant who has been documented as such at the local agency to act on the participant's behalf and, in the case of an infant or child, the caretaker or the caretaker's designee." And a participant is "any pregnant woman, breastfeeding woman, post-partum woman, infant or child who received authorized foods or food instruments under the WIC Program, and the breastfed infant of any participating woman." OAR XXX-XXX-XXXX(17). We agree with petitioner that this language is clear and unequivocal.
Nor are we persuaded by DHS's argument that the rules requiring the state to undertake *359 compliance buys somehow "amend" OAR XXX-XXX-XXXX(5) and OAR XXX-XXX-XXXX(17) or create an exception to those rules. If DHS wanted to amend the definitions so as to include undercover compliance buyers as "authorized shoppers," it could easily do so. In fact, it has done so. OAR XXX-XXX-XXXX(7) (Dec. 27, 2006) now defines "authorized shopper" to include "any DHS representative posing as a participant or participant designee as authorized by DHS." We therefore reject DHS's argument.[6]
Reversed and remanded.
NOTES
[1]  Citations throughout are to Oregon Administrative Rules promulgated January 5, 2004, in effect at all times relevant to this case. The rules have since been renumbered and, in some cases, amended.
[2]  We understand that we are "not to insert what has been omitted." ORS 174.010; PGE v. Bureau of Labor and Industries, 317 Or. 606, 611, 859 P.2d 1143 (1993) (ORS 174.010 applies to determination of statute's plain meaning); id. at 612 n. 4, 859 P.2d 1143 (same interpretative method used for statutes and administrative rules). That precept, however, does not prevent this court or parties before it from attempting to explicate statutes or rules by paraphrasing them, which will necessarily involve the "insertion" of omitted words to the extent that the phrase applies to explanatory clarifications.
[3]  OAR XXX-XXX-XXXX(3)(a)(A) provides for a one-year disqualification upon a showing of "[a] pattern of providing unauthorized food items, in exchange for food instruments, including charging for authorized food provided in excess of those listed on the food instrument." OAR XXX-XXX-XXXX(3)(a)(B) provides for a one-year disqualification upon a showing of "[a] pattern of allowing the purchase of brand names or food types other than those listed on the WIC Authorized Food List."
[4]  OAR XXX-XXX-XXXX provides:

"(1) DHS shall monitor vendors for compliance with applicable laws and rules, including on-site investigation of randomly selected vendors.
"(2) DHS or its authorized representative may conduct compliance buys to collect evidence of improper vendor practices."
[5]  OAR XXX-XXX-XXXX(8) defines "compliance buy" to mean a "single covert, on-site visit in which a DHS representative poses as an authorized shopper and attempts to transact, or transact, one or more food instruments."
[6]  DHS does not advance (and we do not address) the argument that, under the rule, a violation occurs whenever a merchant charges DHS for authorized food that is "not received by an authorized shopper" because, in such transactions, the food is received by an unauthorized shopper. That interpretation differs from petitioner's in that it would permit DHS to find a violation whenever the purchaser is an unauthorized shopper, including every compliance buy; petitioner's interpretation permits DHS to find a violation only when an authorized shopper's purchases are inflated when presented to DHS.
