unit. (ii) Special rules relating to income limitation For purposes of clause (i)— (I) Designation The taxpayer shall designate the imputed income limitation of each unit taken into account under such clause. (II) Average test The average of the imputed income limitations designated under subclause (I) shall not exceed 60 percent of area median gross income. (III) 10-percent increments The designated imputed income limitation of any unit under subclause (I) shall be 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, or 80 percent of area median gross income. . (b) Rules relating to next available unit Subparagraph (D) of section 42(g)(2) of the Internal Revenue Code of 1986 is amended— (1) in clause (i), by striking clause (ii) and inserting clauses (ii), (iii), and (iv) , (2) in clause (ii)— (A) by striking If and inserting In the case of a project with respect to which the taxpayer elects the requirements of subparagraph (A) or (B) of paragraph (1), if , (B) by striking the second sentence, and (C) by striking Next available unit must be rented to low-income tenant if income rises above 140 percent of income limit in the heading and inserting Rental of next available unit in case of 20–50 or 40–60 test , and (3) by adding at the end the following new clauses: (iii) Rental of next available unit in case of average income test In the case of a project with respect to which the taxpayer elects the requirements of subparagraph (C) of paragraph (1), if the income of the occupants of the unit increases above 140 percent of the greater of— (I) 60 percent of area median gross income, or (II) the imputed income limitation designated with respect to the unit under paragraph (1)(C)(ii)(I), clause (i) shall cease to apply to any such unit if any residential rental unit in the building (of a size comparable to, or smaller than, such unit) is occupied by a new resident whose income exceeds the limitation described in clause (v). (iv) Deep rent skewed projects In the case of a project described in