Estimated Payments Remaining

[David Hite]

Good morning everyone!

  I am reviewing my potential first note purchase, and there is an equation I want some input on.  

  In determining how many payments are left, many tapes will have a note maturity date.  There are two types of equations I can run in Excel to estimate the number of payments left on the note.  Both will run from Today's Date until the maturity date and show us the number of months in between.   One will round up, and the other will round down.

  Which one do you use to help understand total number of remaining payments?  I would assume that using the rounding down would be the most effective in predicting returns.  Because its better to underestimate number of payments remaining by one than overestimating by 1.  As well the final payment may only be a portion of the normal payment amount (since last payment on an amort schedule is always smaller/different).

Any info/input on this?

Thank you!

David Hite