If the residential units are rental units, 15% shall be reserved for affordable households. If the units are for-sale, 20% shall be reserved for affordable units. In the event that the 15% or 20% of the total number of residential units does not result in a complete integer, the fraction number of units shall be rounded upward to provide one additional whole unit. For example, if a mixed-use development includes 16 units, the 20% set-aside equals an affordable obligation of 3.2 units. The fractional unit is rounded up to the next integer; therefore, the development would include four affordable units.