We use @(Pega-DecisionEngine:Financial).cumprinc to calculate a balloon payment.

We are getting report from our users that the balloon payment on a loan is not adding up correctly. To get this value we use the following inputs:

Param.ModifiedInterestRateCurrent = 5.75/1200 = 0.004791667
Param.ModifiedTermRemaining = 480
Param.ModifiedBalancePrinicpalCurrent = 77070.33
Param.StartPeriod = 1
Param.TermsToMaturity = 329

With these values we get a cumulative principle of 33003.78 out of pega.
@(Pega-DecisionEngine:Financial).cumprinc(Param.ModifiedInterestRateCurrent,param.ModifiedTermRemaining,Param.ModifiedBalancePrinicpalCurrent,Param.startPeriod,Param.termsToMaturity)

With these values we get a cumulative principle of 33213.93 out of excel.
=CUMPRINC(0.004791667, 480, 77070.33, 1, 329, 1)

Has anyone seen this behavior and have a fix for it?