I am not entirely certain how the Step-by-Step and Forms Mode are linked, programmatically, with respect to the options presented in the disposition section you referenced. However, it is important to recognize that the actual K-1 (Form 1065) does not contain those options; there is only a checkbox for "Final K-1".
Regarding the capital accounts, my understanding is that you, yourself, prepared the 1065 (and associated K-1s) using TurboTax Business. As a result, I would suggest that you make absolutely certain that the return was prepared correctly. First of all, the 2019 program is not fully complete and functional at this point. Additionally, preparing a final return can be somewhat confounding and there is the distinct potential for errors and/or oversights.
In the process of entering your K-1 into the personal version of TurboTax, make absolutely certain you are entering a negative number in the "withdrawals and distributions" box presented in Step-by-Step. Otherwise, the figure entered will be added to your ending capital account.
It might be helpful if you posted the figures and entries on your K-1 here, even if those figures are hypothetical for testing purposes (again note that the program is not ready for filing and there is the possibility errors could result and/or there could be bugs in the software).
Finally, you might want to contact Support (link below) during regular business hours.
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
