Idaho estimated tax form 51--changed amounts

[ajp]

In April, I used form 51 and the limited amount of information I had at the time to calculate the estimated tax payment for a client.  They sent in the amount (80% of estimate).  In October, when I filed the return, form 51, line 2 was changed to be the ACTUAL amount, not the estimated amount for tax due.  Therefore, the 80% was no longer accurate.  My clients now have a decent penalty.  I am concerned that the October version is what Idaho thinks we predicted back in April.  However, Idaho is a state that Proseries doesn't file the extension electronically.  I am not sure if client sent the entire form or if they just cut off the payment coupon.  Is this something we can argue Idaho over?  

In the future, I won't use the 80% of estimated method.  I will use 100% of prior year method.

[dkh · Accepted solution]

I'm not familiar with Idaho Form 51 - but - my guess is Idaho doesn't really care what information you used back in April.  The penalties will be calculated based on the final return.   If it were me, I'd ask Idaho for a waiver of penalty - worse case scenario - they say no.