We reverse the final judgment and remand to recompute the amount owed. Though we agree with the trial court that no default rate could apply to the balance due under the note prior to acceleration, here the date Appellant filed suit on the note, we hold it was error not to award Appellant 18% interest, in accordance with the specific terms of the Appellees’ agreement, on deferred interest from the date that the interest was past due and unpaid, July 15, 1989, through the date suit was filed. See Breitbart v. Zaucha, 185 So.2d 496 (Fla. 3d DCA 1966). We find no error as to the balance of the final judgment.