Credits against development impact fees shall not be given for: a) project improvements; or b) any construction, contribution or dedication not agreed to in writing by the city prior to commencement of the construction, contribution or dedication. Credits issued for one city capital improvement may not be used to reduce development impact fees due for a different capital improvement. No credits shall be issued for system improvements contributed or dedicated prior to the effective date hereof. (Ord. 985 § 1, 2007)