The most common misconception is your payoff is the balance shown on your previous mortgage statement. The payoff is actually your Unpaid Principle Balance plus interest per diem paid until the lender is paid in full. So if you made your last payment to your former lender on May 1st and you close on your new loan on May 15th and fund on May 18th, this means your other lender most likely won’t get the funds to pay them in full until May 25th. So 25 days of interest per diem would be collected on top of your UPB.
UPB = $324,456
Interest Per Diem = $68.15
$324,456 + ($68.15*25) = $326,159.75