For a typical mortgage (with the 360-day interest calculation), in order for the system to post your payments correctly, if you have more than one payment to make you must make each one separately. For example, if your mortgage payment is normally $1,000 and you want to make two payments, you must do two separate transfers of $1,000 each. (If you tried to transfer $2,000 at the same time, the first $1,000 would make your payment and the rest would go directly to principal only.)