After considerable research and scrolling down to the bottom of the "Federal Asset Entry Worksheet", I found I needed to enter BOTH the asset class and the recovery period. The interview asks only for the asset class, and recovery period must be entered manually in the worksheet form. I found asset class selection does not change the result except, if an unacceptable class is chosen, no depreciation will be calculated in that event either.
Thanks for your interest and offers of help.
Bob
