1. Net Acre. For the purposes of this section, a net acre is the total development acreage net of undevelopable lands (as defined in Chapter 18.15 TMC) and a 24 percent reduction allowing for infrastructure. Development projects less than one and one-half acres in size do not need to subtract infrastructure allowance. Development proposals one and one-half acres or larger may not exempt one and one-half acres from calculating infrastructure allowance.