Building owners may choose to use this appendix to achieve an additional 6 percent savings in building energy use. The number of additional energy efficiency credits required by Section R406.3 would be increased by the following amounts:

1.0 credit for each new single-family, two-family and townhouse dwelling unit.

0.5 credit for each new dwelling unit within an R-2 occupancy building.

0.5 credit for each addition smaller than 500 square feet to a single-family, two-family or townhouse dwelling unit.

1.0 credit for each addition of 500 square feet or larger to a single-family, two-family or townhouse dwelling unit.

Where Section R405, Simulated performance alternative, is used, the maximum allowable energy consumption shall be 92 percent of the value calculated according to Section R405.3.