Ala. Code § 45-51-243.08: Credit Collections.

Any person who is charged with collecting the rental tax and who makes cash or credit leases or rentals, may report such cash leases or rentals when made, and shall thereafter include in each monthly report all credit collections made during the month preceding, and shall remit the tax due thereon at the time of filing the report, but in no event shall the tax be owed by the lessor or vendor until collections of the credit leases or rentals have been made.