Can a landlord make changes to extend pro rated rent?

My apt was not ready until the 5th of the month and they prorated the rent but my rent was always due on the 1st. I gave a 30 day notice to vacate on the 1st of the month and was told I would have to pay for those additional (5) days that were prorated even though I was moving out on the 31st of the month. I received my itemized security deposit account but they deducted (7) days instead of (5). I left the place extremely clean even though I figured they would charge me a cleaning charge which they didn't. Should I just leave well enough alone as I am so happy to be out of there anyway?