Turbo Tax calculated the incorrect taxable amount on the 1040 line from an OPM (federal) 1099-R entry, which is different from the 1099-R. Info entered correctly. Why?

[nutin2it]

I entered the gross distribution and the amount in box 2a. shown as the taxable amount, along with the total employee contribution in box 9b.  TT calculated the taxable amount $95 lower than shown on the 1099-R for some reason - totally ignoring what I entered as the taxable amount.

[ColeenD3]

Since you had employee contributions, these are prorated and deducted from your taxable amount each year.

[dmertz]

This sounds like you inappropriately told TurboTax to use the Simplified Method to calculate a different taxable amount.  Delete and reenter the Form 1099-R and indicate that the box 2a amount is the correct taxable amount.