(3) The dollar amount calculated under Section 37.3(a)(5)(B)(vii)(2) shall be divided by two (since a 50% passthrough is permitted), and then divided by the total number of units covered by the water bill, including commercial units. The resulting dollar figure shall be divided by the number of months covered by the water bill cycle (most are two-month bill cycles), to determine the amount of that water bill that may be passed through to each residential unit for each month covered by that bill.
(4) These passthroughs may be imposed on a monthly basis. These passthroughs shall not become part of a tenant's base rent. The amount of each passthrough may vary from month to month, depending on the amount calculated under Sections 37.3(a)(5)(B)(vii)(1) through (3).
(viii) The Board may amend its rules and regulations as necessary to implement this Section 37.3(a)(5)(B).
(6) Property Tax.