dissenting.
Plaintiffs third claim for relief alleged that it was an intended third-party beneficiary of an agreement between Russell and Aetna. Under the terms of that express agreement, plaintiff alleged, Aetna became indebted to pay plaintiff the “reasonable amount” of Russell’s medical bills. Plaintiff quoted from the agreement, which sets out Russell’s claim of $98,872 in medical expenses incurred at plaintiffs facilities, contains provisions calling for Aetna to be ‘ ‘solely responsible for resolving the claims” and provides that “the sums heretofore set forth [are] to be the sole responsibility of the carrier Aetna Casualty & Surety Company.” On the basis of those allegations, the claim was tried by both parties on a theory of express contract. It was submitted to the jury on a theory of express contract, and the jury returned a verdict in plaintiffs favor on a theory of express contract.
Now, on appeal, the majority “deems” plaintiffs claim to have been predicated on an entirely different theory, and finds plaintiffs evidence wanting because it fails to satisfy all of the elements of that theory. Specifically, the majority finds fatal plaintiffs failure to present evidence of the necessity of the services it provided Russell. That plaintiff should be found to have failed to establish all the elements of a claim for quantum meruit comes as no surprise. It was not the theory under which its claim was pleaded, tried, presented to the jury or decided.
The majority points to the mention of two words — “reasonable amount” — in plaintiffs complaint, as the basis for its decision. In so doing, the majority makes two mistakes. First, it ignores the balance of the complaint, which alleges recovery on the basis of express contract. According to plaintiff, the contract itself expressly defined the “reasonable amount” for services rendered. Where there is a written agreement regarding payment for services rendered, the amount stated in the agreement is sufficient to evidence the value of the services rendered. Grant v. Yok et al, 233 Or 491, 495, 378 P2d 962 (1963). Thus, the lack of evidence as to necessity of treatment is of no consequence; it is, in fact, irrelevant. Second, even if that were not the case, the court lacks authority simply to “deem” a complaint to state a claim on a different theory from what is alleged. The majority cites *194Gillman v. Emel, 89 Or App 153, 747 P2d 390 (1987). However, I have searched that opinion in vain for any mention of the sort of action the majority takes in this case.1
The question for us is whether plaintiff presented any evidence to support its claim under the terms of the express agreement. It is not for us to test plaintiffs proof against a theory never so much as contemplated at trial. Instead of disposing of this case on the quantum meruit theory, I would evaluate Aetna’s assignments of error against the case as it was tried.
Aetna assigns error to the trial court’s denial of Aetna’s motion for a directed verdict. Aetna argues that there was no evidence of a third-party beneficiary contract. The argument requires us to construe the terms of the agreement between Aetna and Russell. In construing those terms, we first determine whether the contract is ambiguous. If it is not, then we decide the matter as a question of law. If it is, then we determine whether there was evidence of the parties’ intentions sufficient to go to the jury as a question of fact. OSEA v. Rainier School Dist. No. 13, 311 Or 188, 808 P2d 83 (1991); Thompson v. Bolliger, Hampton & Tarlow, 118 Or App 700, 709, 849 P2d 526, rev den 317 Or 163 (1993).
There is no question but that the agreement between Aetna and Russell is ambiguous. It sets forth specific amounts Russell claims he incurred for medical services and then provides, several paragraphs later, that “the sums heretofore set forth [are] to be the sole responsibility of the carrier Aetna.” Whether “the sums heretofore set forth” refers to the expenses Russell incurred, as plaintiff contends, or to some other expenses referred to in the contract, as Aetna contends, is not at all clear from the language. Therefore, *195construction of the term is a factual question, which could not properly have been taken from the jury by way of directed verdict. The trial court, therefore, did not err in denying Aetna’s motion.
Aetna next assigns error to the trial court’s denial of its motion to strike the testimony of an employee of plaintiff that the amounts of Russell’s medical bills were reasonable. It also assigns error to the trial court’s denial of Aetna’s motion for a directed verdict based on the absence of any admissible testimony that the services plaintiff provided to Russell were reasonable and necessary. However, in both cases, because the jury decided this case on the basis of an express contract, testimony concerning the reasonableness or necessity of the services is irrelevant. Grant v. Yok et al, supra, 233 Or at 495; see also Schade v. Muller, 75 Or 225, 232, 146 P 144 (1915). The trial court did not err in denying Aetna’s motions.
The decisions of the trial court should be affirmed. Therefore, I dissent.
In Gillman, the plaintiff sued her employer to recover unpaid sales commissions. She brought two claims, one on a theory of express contract and the other on a theory of quantum meruit. The defendant counterclaimed for overpayment of wages, on a theory of express contract. The trial court submitted the contract claims to the jury. When the jury returned its verdict in favor of defendant on both the first claim and the express counterclaim, the trial court set aside the verdict and found for plaintiff on the quantum meruit claim. We reversed, holding that because the jury had ruled in favor of the defendant on the express contract claims, it was error for the trial court to have entered judgment in favor of plaintiff on the quantum meruit claim. We said nothing about “deeming” for the first time on appeal a claim brought on a theory of express contract to be one brought under quantum meruit or any other theory.