(4) Applications Filed On or After [May 1, 2002 or 60 days prior to passage of this Ordinance on Second Reading, whichever is later], for Other Work and Improvements On Properties With Five Residential Units or Less. For applications filed on or after [May 1, 2002 or 60 days prior to passage of this Ordinance on Second Reading, whichever is later], the following provisions shall apply to certification of all work and improvements for properties containing five residential units or less, with the exception of work and improvements costs certified for passthrough under Subsections 37.7(c)(2) or (3):
(A) Amortization Periods. Costs shall be amortized on a straight-line basis over a ten, fifteen or twenty-year period, depending upon which category described below most closely relates to the type of work or improvement and its estimated useful life.