Loan amortization + payment from RKs

[YogaTPA]

I work with a recordkeeper whose calculated loan payment never seems to match the one that I calculate. I generally use a standard loan amortization schedule (a spreadsheet and I also coded one in Python), and have cross-checked it on multiple online calculators (those calculators almost always match the one I get, perhaps off by a penny).

I asked the recordkeeper about it and got a very vague answer - that it depends on the interest rate and on the time period.

Has anyone else experienced this, and if so, have you gotten an answer to the discrepancies?

Part of the reason I am asking is because I like to generate my own amortization schedule and when a payment is off by even $.10, it adds up over 5 years and makes my schedule wonky even if I try to override the payment amount. I really want to know what is going on with their calculator.

[ETA Consulting LLC]

I guess you'd have to try and ascertain their method for calculating the loan payment.  A few easy things that "MAY" throw it off is the first payment date.  Ideally, it should match using a basic calculation with the number of periods (i.e. 26 if bi-weekly) and annual interest rate (compounded for that number of periods).  This can get thrown off if the recordkeeper's system is actually incorporating the date of first payment to be one other than 'exactly two weeks' (again, assuming bi-weekly payroll).  

I don't know, but merely suggesting the approach of trying to ascertain their logic since they are the ones whose numbers you'll end up trying to match.

Good Luck!

[YogaTPA]

FWIW, I did get a little bit more detailed of an answer. They called me back and said the discrepancy is probably due to three things:

1. Rounding
2. Timing
3. Fees added

(I tried adding in fees in varying amounts but couldn't match their number, but I guess this is more info than I had two days ago.)

At some point I will get hold of an amortization schedule and try to nail it down once and for all!

[Lou S.]

Is the date of first repayment date longer than the  regular loan period and is interest accrued daily? If so it's probably the first payment throwing off the calculation.

[YogaTPA]

Lou, that could be it too. Thanks