You are absolutely correct, the form now says to complete lines 1-4, Part I and part II for all years of the installment sale.
Please look to see if the amount from line 26 is carrying to the correct forms and lines of those forms even if you don't see it on a worksheet?
When you complete the information requested in the Installment sale section of TurboTax, it carries the amount from the Form 6252 line 26 to the Form 4797 line 4 or Form 4797 line 10, depending on the holding period of the property sold. Then, if the property was section 1250 property TurboTax carries it into Sch D.
