Upon an action upon an account, appellant sued respondent for labor and materials required to install a water system, having previously billed respondent for $53,-892.84, crediting $35,863.47, and claiming a balance due of $18,029.07. The jury returned a verdict for exactly the latter amount, the case having been submitted to it under MAI 26.03 (form for action on account) thus:
“INSTRUCTION NO. 7
“Your verdict must be for plaintiff if you believe:
“First, at defendant’s request plaintiff furnished to Nehai Tonkayea Lake Association, Inc., certain material and labor between August 25, 1977 and May 23, 1978, and
“Second, plaintiff charged a total of $53,892.84 for such material and labor of which only $35,863.47 was paid, and
“Third, plaintiff’s charges were reasonable.
“Unless you believe plaintiff is not entitled to recover by reason of Instruction No. 10.”
[The tail encompassed an instruction under recoupment or counterclaim, the jury finding against the issue, which is not here presented.]
A proper damage Instruction No. 9 on the submission of the action on account was given under MAI 4.04, modified. See Hereford Concrete Products v. Aerobic Services, Inc., 565 S.W.2d 176, 178[5] (Mo.App.1978), approving such a submission. Instruction No. 9 is: “If you find in favor of Plaintiff, then you must award it the reasonable value of the material and labor furnished with six percent (6%) interest thereon from May 23, 1978 to June 30, 1979, and at nine percent (9%) thereafter.” [Plaintiff stated to the court that the interest submission was error, and judgment was therefore entered on the jury’s verdict of principal only, so there is no issue as to interest being awarded.] Note that the Hereford case states that the submission of the damage instruction, “reasonable value,” followed the same words of the action on account instruction under MAI 26.03.
The difficulty here is that the court gave another damage instruction, No. 8, “If you find in favor of Plaintiff, Kunkle Water and Electric, Inc., on plaintiff’s claim for damages, then you must award plaintiff such sum as you believe will fairly and justly compensate plaintiff for any damages you believe it sustained as a direct result of the conduct of defendant as submitted in Instruction No. 7.” The trial court found “that the giving of the two damage instructions did not confuse the jurors and did not prejudice the outcome of the case”, but nevertheless, ruled that it should not be done or tolerated in the courts, and granted a new trial on that basis. Instruction No. 8 is apparently a modification of MAI 4.01, modified, entitled “Damages-Personal and Property”, and under plaintiff’s theory of action on account, it was erroneous.
Rule 70.01(b) provides that whenever MAI “contains an instruction applicable in a particular case which the appropriate party requests or the court decides to submit, such instruction shall be given to the exclusion of any other on the same subject.” As noted, MAI 4.04 was the appropriate instruction, modified to include “material and labor” instead of “goods” furnished. The giving of Instruction No. 8 was error, but under Rule 70.01(c), its prejudicial effect must be judicially determined.
Respondent contends in argument that the giving of Instruction No. 8 allowed the jury to award appellant “any damages” it sustained, saying that appellant introduced *179evidence of additional items of damage beyond labor and material furnished (properly submitted in Instruction No. 9, supra), i.e., hotel bills and meals for employees, and per mile charges on vehicles. The argument would have validity if the jury returned a verdict including amounts for those items, but it did not do so. Appellant’s documentary evidence showed $18,029.07 for labor and materials furnished, the amount prayed therefor in the petition (exclusive of $1,038.81 sales tax claimed). The jury’s verdict was for $18,029.07, and no more as for principal due. The error in giving Instruction No. 8 was cured by the verdict, and respondent does not contend that the amount thereof is excessive. Compare Matulunas v. Baker, 569 S.W.2d 791, 796, et seq. (Mo.App.1978), a warranty of habitability case in the sale of a new home in which MAI 4.01 submitted a diminution in value theory. The jury did not follow plaintiffs’ evidence of decrease in market value, but returned a verdict for the exact costs for labor and material in effecting repairs. The court found no prejudicial error on those facts.
The giving of the second and erroneous damage instruction is not here condoned or approved. It is simply that there exists no prejudicial error.
The judgment is reversed and the case is remanded with directions to reinstate the verdict for plaintiff in the amount of $18,-029.07.
All concur.