Retirement tax questions

I plan to call Turbo Tax  and maybe the IRS today as I am was concerned before and am very concerned. For regular IRAS I see that Turbo Tax carries forward a reduced basis  figure from last year's 8606 but  the IRS instructions are different from what Turbo Tax does. The IRS 8606 instruction book refers each year to the last 8606 you filed for Line 2 I think it is. So I may have several years

of incorrect reporting. I even called the IRS last year and they said the basis does not change.  If there is anyone else that can speak to the IRS instructions which are online and what Turbo Tax does,please let me know soon.