some discussion, Mr. Schepps wrote the following handwritten amendment to the lease:
Contract signed this date may be can-celled after one year with payback of the 11% discount.
If contract is cancelled between the 3 year and 5 year a 4% payback of discount will be assessed.
In either event, interest on these amounts would be assessed.
This handwritten amendment was signed and dated by appellee’s representative.
Billing on the subject lease commenced on May 1, 1972. The lease was terminated by appellants on April 1, 1975, thirty-five (35) months after the effective date of the agreement. On April 17, 1975, appellee sent appellant an invoice for payback of the 11% discount or a sum of $35,954.70, “Interest at Current Prime Rate” or a sum of $4,249.98, and sales tax on those items. No part of that invoice was paid. Thereafter, appellee brought suit for the discount “plus interest thereon from April 17,1975, to date of judgment.”
Appellant defended the suit by asserting the affirmative defenses of failure of consideration, breach of warranty and contract, and usury. It also counterclaimed against appellee on the grounds of failure of consideration and usury. At the conclusion of the evidence in the trial, the case was submitted to the jury on special issues. Judgment was entered that appellee recover from appellant $38,954.70, interest thereon at the rate of six percent (6%) per annum from April 17,1975 to date of judgment or the sum of $14,023.69, and attorney’s fees in the sum of $10,100.
Appellant brings forward twenty points of error. Its points of error 1, 2, 3 and 4 concern the defense of failure of consideration. Appellant asserts that the evidence established this defense as a matter of law and that the jury’s answers to Special Issue Nos. 3, 4 and 5 were contrary to the great weight and preponderance of the evidence. It further asserts that the trial court erred in granting judgment based on those answers because it had previously ruled that there was a failure of consideration thus making the answers irrelevant, immaterial, and mere surplusage.
During the proceedings on the parties’ objections and exceptions to the charge, the court stated: “I find from the preponderance of the evidence that there was failure of consideration.” However, the court submitted Special Issue No. 3 which inquired as to whether appellee failed to provide the necessary service and parts to maintain the computer in good operating condition. It is not uncommon for a trial court to change its ruling on a particular issue as it is in the best position to construe its own ruling. In this case, the trial court either mistakenly made this statement or decided there was enough evidence to submit the issue. Appellant relies on Kunkel v. Poe Land and Development Company, 393 S.W.2d 191 (Tex.Civ.App.—Corpus Christi 1965, no writ), for the proposition that the issue of failure of consideration is a legal one within the province of the trial court and not the jury. While we do not dispute the correctness of this statement, Kunkel is distinguishable because there the issue submitted to the jury inquired as to whether the evidence “constituted failure of consideration.” The court held: “It was the duty of the court (not the jury) to determine whether there was a failure of consideration in this case based upon ultimate facts found by the jury or conclusively established.” 393 S.W.2d at 195. (emphasis ours) Consequently, in the instant case, the court’s submission of Special Issue No. 3 was proper.
Appellant further asserts that there was no evidence and insufficient evidence to support the jury’s answer to Special Issue No. 3. In considering all the evidence, we find the jury’s verdict was not so contrary to the great weight and preponderance of the evidence as to be manifestly unjust. In re King’s Estate, 150 Tex. 662, 244 S.W.2d 660 (1951). See Calvert, "No Evidence” and “Insufficient Evidence” Points of Error, 38 Texas L.Rev. 361 (1960). There was testimony to the effect that the service appellee provided appellant was