TurboTax Premere had (has) an error on Form 2210, Line 10, Box a. The calculated value was not the same as either of two candidate values (the OR (Otherwise)) condition in the instructions.
After getting help from their helpline, it turned out the fix (a workaround) was to place an "X" in D in Part III of Form 2210. This was changed by redoing the interview. I had had an X in both C and D. TurboTax got (gets) confused when both C and D are Xed.
Quite frankly, I don't know what the difference between C and D is, but it works right with only D.
TurboTax should fix this defect, but the workaround is ok
