Unfortunately, @mgj30327, the Debt Planner template has a relatively simple lookup by purely the account name. (Some of our other templates use more complex lookups to uniquely identify accounts by their Account IDs or combinations of fields like Account Name and Account #.)
I just checked the template and that Account-name-only lookup is implemented in several cells and columns and would be non-trivial to remap. Your best bet is probably creating unique account names for the two accounts by renaming the account in the Tiller Money Console and then using the Repair Balance History workflow to reflect that name change throughout your Balance History sheet.