I've been in this business for a while... my daughter would tell you I'm old as dirt... and for as long as I've been in this, we've had a complicated way of calculating FHA Downpayment.

FHA always used acquisition cost.  How much were you putting into the total aquisition of the property... closing costs and downpayment combined.

With the new rule changes of January 1... we use a STRAIGHT UP number.  The base loan will be a 96.5% of the sales price or appraised value - whichever is LESS.  If you are working with a loan officer is is unfamiliar with FHA - you could find yourself at the closing table wishing you'd done a little more research. I just saw a deal where the loan officer quoted the wrong downpayment amount by $1200.

Do your research!  Work with someone who KNOWS the guidelines!