PER CURIAM.

Defendant Harris appeals and plaintiffs cross-appeal a bench opinion of the Wayne County Circuit Court. Plaintiffs also appeal the trial court's ruling dismissing plaintiffs' claim of fraud and malpractice against defendant Arthur Young Company.

Defendant Harris is the general partner of the Book Building Company, a Michigan limited partnership formed in 1958. Plaintiffs are limited partners of said company representing an 8% partnership interest. Defendant Arthur Young is an accounting firm which audited the books and records of the Book Building Company for the years 1967-1976. Further facts will be added where necessary in the discussion of the issues.

Before considering the merits of this appeal, we first must determine what effect, if any, an October 6, 1981, decision by this Court had on the instant action. Originally plaintiffs brought derivative claims on behalf of said company. Defendants filed motions for summary judgment with respect to the derivative claims. The motions were granted by the pretrial judge. Plaintiffs appealed the order granting summary judgment to this Court. We reversed the trial court, holding that plaintiffs could maintain a derivative suit on behalf of the partnership. See Jaffe v Harris, 109 Mich. App. 786; 312 N.W.2d 381 (1981), lv den 414 Mich. 925 (1982). That decision, however, was rendered after the parties had proceeded to trial on their individual claims. Plaintiffs assert that, as a result of our earlier decision, the instant appeal should be transformed into and proceed as a derivative suit. We disagree. The trial court made its findings based on plaintiffs' individual claims. To now view plaintiffs' claims as derivative would considerably alter the posture of this appeal. Accordingly, we conclude that the instant appeal is to proceed, as did the trial at issue, on plaintiffs' individual claims.

Defendant Harris claims the trial court improperly granted plaintiffs' recovery upon the management fee claim. The trial court found that there was no agreement by the limited partners to amend the partnership agreement so as to increase the management fee and that plaintiffs were entitled to their allocable share of said fee retroactive for the period to January 1, 1970. Defendant Harris raises three objections to the trial court's findings. First, he claims the management fee claim is barred by the six-year period of limitation for a contract action. MCL 600.5807(8); MSA 27A.5807(8). We disagree. We hold that the trial court was correct in setting the commencement of plaintiffs' action at the time of former plaintiff Jaffe's commencement of the action in 1974. See GCR 1963, 118.4; Plowman v Satkowiak, 22 Mich. App. 425; 177 N.W.2d 641 (1970); Doan v Chesapeake O R Co, 18 Mich. App. 271; 171 N.W.2d 27 (1969). Second, defendant claims plaintiffs are not entitled to reimbursement for the increase in management fees paid to defendant between January 1, 1970, and January 24, 1973. We disagree. Defendant's implied assertion that the relations between the parties were such as to justify his expectation of a reply to a 1970 letter is unsubstantiated by the record. Looking to the acts of the parties and applying an objective standard, Banque de Depots v National Bank of Detroit, 491 F.2d 753 (CA 6, 1974), it is apparent that the plaintiffs relied on ¶ V of the partnership agreement as setting the maximum management fee and reasonably believed that said fee could not be increased via a mere letter to the partners. The trial court was correct in finding no assent to the additional compensation. We agree with defendant Harris's final objection that the trial court improperly awarded interest on the management fee claim for the period preceding commencement of the action. Interest should be awarded as interest on judgment. MCL 600.6013; MSA 27A.6013. However, we hold the date of the filing of plaintiffs' action to be the date of the original complaint in 1974, not the date of plaintiffs' intervention as defendant contends. Michigan Mutual Liability Co v Staal Buick, Inc, 41 Mich. App. 625; 200 N.W.2d 726 (1972); Oakwood Homeowners Ass'n, Inc v Marathon Oil Co, 104 Mich. App. 689; 305 N.W.2d 567 (1981).

Next, defendant Harris claims that the trial court improperly failed to apply the appropriate statute of limitations with regard to the withdrawal issue. The trial court ruled that defendant Harris was guilty of fraudulent concealment of the cause of action relating to improper withdrawals made from 1960 to 1973. Harris allegedly used the money for his own personal use and returned it at the end of the year without compensating the partnership for the use of the funds. Defendant Harris raises several objections. First, defendant claims the pretrial judge's ruling that there was no fraudulent concealment on the part of defendant Arthur Young applied equally to him. We disagree. Defendant Harris neglected to make a pretrial motion as to the issue of fraudulent concealment and hence the issue was not properly before the pretrial judge. The trial court properly made an independent determination as to the issue of fraudulent concealment on the part of defendant Harris.

Second, defendant Harris claims the trial court's ruling that he was guilty of fraudulent concealment was clearly erroneous. We disagree. See MCL 600.5855; MSA 27A.5855; De Haan v Winter, 258 Mich. 293, 296; 241 N.W. 923 (1932). Moreover, see Van Stee v Ransford, 346 Mich. 116; 77 N.W.2d 346 (1956); Penner v DeNike, 288 Mich. 488; 285 N.W. 33 (1939); Gaetzi v Carling Brewing Co, 205 F. Supp. 615, 620 (ED Mich, 1962). Finally, we reject defendant's claim that the applicable period of limitation for the withdrawal issue is three years where plaintiffs seek damages for loss of financial expectation as in the instant case. This action is governed by the six-year period of limitation. Borman's, Inc v Lake State Development Co, 60 Mich. App. 175; 230 N.W.2d 363 (1975); George v Petoskey, 55 Mich. App. 433; 223 N.W.2d 6 (1974).

Defendant Harris also claims that the trial court utilized an improper measure of damages with respect to the withdrawal claim. The trial court concluded that it had discretion to award interest as damages utilizing varying rates of interest each year with such interest to be compounded annually from the date of the first withdrawal. Defendant Harris makes four objections to this ruling which will be discussed seriatim. First, defendant claims that plaintiffs failed to prove a right to an individual recovery. We find that plaintiffs sufficiently demonstrated the basis of their recovery, and the risk of uncertainty as to the extent of said recovery was properly cast upon defendant Harris as the wrongdoer. See Hayes-Albion Corp v Kuberski, 108 Mich. App. 642, 653-656; 311 N.W.2d 122 (1981). Second, defendant Harris claims that the trial court improperly awarded interest at variable rates as damages. A review of the findings herein reveals that the damages awarded had a reasonably certain basis. Moreover, the findings were not clearly erroneous since each rate of interest utilized was supported by competent evidence. See Killefer v McClain, 78 Mich. 249; 44 N.W. 405 (1889); 25 CJS, Damages, § 92(1), p 986; Helzer v Local 98, United Ass'n of Journeymen Apprentices of Plumbing Pipefitting Ind of United States Canada, 97 Mich. App. 376; 296 N.W.2d 28 (1980). Third, defendant Harris claims that the trial court exceeded its authority by determining that the interest to be paid as damages should be compounded. We disagree. See Perrin v Lepper, 72 Mich. 454, 555; 40 N.W. 859 (1888); Schwartz v Piper Aircraft Corp, 90 Mich. App. 324, 326; 282 N.W.2d 306 (1979). Finally, defendant Harris claims that the trial court improperly allowed a rate of interest higher than the statutory rate after the commencement of the action. Again, we disagree. The interest awarded in the instant case was the damage. The damages continued after suit was filed since Harris did not repay the funds. We agree with the trial court that Harris would recieve a substantial unjustified benefit if we were to only allow the legal rate of 6% after 1974. See Perrin, supra. He would have received the benefit of the use of the funds at less than the market rates even though he was an admitted wrongdoer. Moreover, in contrast to Vannoy v City of Warren, 26 Mich. App. 283; 182 N.W.2d 65 (1970), there is no indication that the computation of interest utilized herein resulted in a double recovery.

Plaintiffs contend on cross-appeal that the trial court improperly dismissed plaintiffs' claim with respect to the issue of management expenses. Our review of the record and the applicable paragraphs of the limited partnership agreement reveals that the trial court's ruling was proper and not clearly erroneous. See GCR 1963, 504.2; Warren v June's Mobile Home Village Sales, Inc, 66 Mich. App. 386, 389; 239 N.W.2d 380 (1976); Illenden v Illenden, 46 Mich. App. 710, 715-716; 208 N.W.2d 565 (1973), lv den 390 Mich. 783 (1973).

With regard to defendant Arthur Young, plaintiffs first contend that the trial court improperly dismissed plaintiffs' fraud claim. This contention is without merit. See Cormack v American Underwriters Corp, 94 Mich. App. 379, 385; 288 N.W.2d 634 (1979); Kwasny v Driessen, 42 Mich. App. 442; 202 N.W.2d 443 (1972). Additionally, plaintiffs contend that the trial court improperly dismissed plaintiffs' malpractice claim. We disagree. See MCL 600.5838; MSA 27A.5838; MCL 600.5805; MSA 27A.5805. We further find that the trial court's rejection of plaintiffs' expert testimony explaining plaintiffs' continuing duty theory was not clearly erroneous. See Illenden, supra; Warren, supra.

Finally, we reject defendant Arthur Young's claim that defendants are entitled to an award of damages and expenses on appeal for the reason that plaintiffs' cross-appeal is frivolous and without merit. We hold that plaintiffs' appeal is neither frivolous nor vexatious. Molony-Vierstra v Michigan State University, 101 Mich. App. 353; 301 N.W.2d 18 (1980).

Affirmed with modifications in accordance with this opinion.