Plaintiff appealed from a judgment of the trial court ordering it to compute its mortgage payments to defendant on the basis of “gross sales”.

The issues are: ambiguity of the contract and interpretation thereof by the court.

We affirm.

Following two years of negotiations, plaintiff signed a promissory note and mortgage in favor of defendant for $975,-000.00. The note provided for interest at the rate of 9'/2 percent per annum plus 15% of “annual room revenues” in excess of $370,000.00. Three years after the agreement was signed, plaintiff for the first time contended that the phrase “annual room revenues” meant “gross sales less the cost of sales” rather than “gross sales”. It paid the interest calculated on gross room sales under protest and then filed suit for a declaratory judgment to define the phrase “annual room revenues” as it contends or in the alternative to declare the clause void for vagueness. The court ordered plaintiff to compute its interest on the basis of gross room sales.

Plaintiff’s claim that the contract is ambiguous and should be construed against defendant is without merit. The loan application, addendum (prepared by defendant), loan commitment and other correspondence *671between the parties over a two year period reveal the terms “gross room sales” and “annual room revenue” were used interchangeably. We find no error in the court’s determination that it was the mutual intent of the parties to base plaintiff’s additional interest on participation in “gross room sales”.

For the above reasons, the judgment of the trial court is affirmed at appellant’s costs.

AFFIRMED.