Example: I closed on a $500K mortgage on 6/20. At that time I paid pre-paid interest from 6/20 to 7/1. As such, starting on July 1 I still owe $500K. The first payment, due August 1, will be for principal and interest for July 1 to July 31.
In Quicken, when I add a new Loan - Mortgage, it asks me for the "Opening Date"… do I enter 6/20 (the day I closed) or 7/1 since I did not make the first payment until 8/1? (My current guess is to use 7/1.)