All fees and charges created by sections 13.30.010 to 13.30.150 are retroactive fees, with the charges billed in the ensuring billing period for services provided in the prior period. Proration of all incurred charges shall be based on the billing period as defined in this section of the code, and shall be due and payable in the ensuing billing period as provided in the Wood Village Municipal Code for the provision of water or sewer services.