So I'm in the same boat.  Changed bank accounts, but forgot to change the account in the drop down menu in payroll settings.  Great questions, how does the program not throw up an alert, and how is it not possible to simply change the account after the payroll has completed?  There are a lot of frustrating things about QBO that should be easy to fix.  I've regretted my decision to use QBO and extremely frustrated with it.  My office manager with 30 years experience has never had so many issues with this type of software.