How to calculate cumulative shareholder bases (lines 1 and 2 of the new 7203 forms) to take S Corp losses this year? We have K-1s and 1120-S forms going back 16 years.

TurboTax's new 7203 form is reporting zero for lines 1 and 2. I did not enter these numbers.

Another question is about line 36 losses for this year (column a) and carryover loss (column b). Quicken filled in only last year's loss in column b. Shouldn't the carryover amount also include losses from two or more years ago? According to IRS prior year's carryover was supposed to be on the worksheet required from 2018 to 2020 (similar to the new form 7203). However, Turbotax never sent me that worksheet.