In the event the Board determines during any year that there are insufficient projects in process to use the total allocation of permits for housing units affordable by low and moderate income households for that year, the Board may allocate the excess permits for other housing units; provided, however, that the number of housing units for the succeeding year(s) shall be adjusted to the end that, on the average, not less than 15 percent of newly constructed units during any three consecutive years shall be affordable by low and moderate households. (Ord. 2836, 1/8/80; 3328, 11/23/82)