Retirement tax questions

I have a related question.  I am a retired Maine state employee and am working on my 2020 state tax return in TurboTax.  On the "Previously Taxed Retirement Benefits" page, it says to subtract the amount in box 14 of the 1099-R from box 2a.  If I do that, I get a large deduction, much larger that previous  years.  The instructions on the Maine I-File site say to  subtract the amount in box 16  from box 2a, which gives a smaller result consistent with past years.  Is this an error in the TurboTax instructions?