(2) Definitions and special rules For purposes of this subsection— (A) Qualified project period The term “qualified project period” means the period beginning on the 1st day on which 10 percent of the residential units in the project are occupied and ending on the latest of— (i) the date which is 15 years after the date on which 50 percent of the residential units in the project are occupied, (ii) the 1st day on which no tax-exempt private activity bond issued with respect to the project is outstanding, or (iii) the date on which any assistance provided with respect to the project under section 8 of the United States Housing Act of 1937 terminates. (B) Income of individuals; area median gross income (i) In general The income of individuals and area median gross income shall be determined by the Secretary in a manner consistent with determinations of lower income families and area median gross income under section 8 of the United States Housing Act of 1937 (or, if such program is terminated, under such program as in effect immediately before such termination). Determinations under the preceding sentence shall include adjustments for family size. Subsections (g) and (h) of section 7872 shall not apply in determining the income of individuals under this subparagraph. (ii) Special rule relating to basic housing allowances For purposes of determining income under this subparagraph, payments under section 403 of title 37 , United States Code, as a basic pay allowance for housing shall be disregarded with respect to any qualified building. (iii) Qualified building For purposes of clause (ii), the term “qualified building” means any building located— (I) in any county in which is located a qualified military installation to which the number of members of the Armed Forces of the United States assigned to units based out of such qualified military installation, as of June 1, 2008 , has increased by not less than 20 percent, as compared to such number on December 31, 2005 , or (II) in any county adjacent to a county described in subclause (I). (iv) Qualified military installation For purposes of clause (iii), the term “qualified military installation” means any military installation or facility the number of members of the Armed Forces of the United States assigned to which, as of June 1, 2008 , is not less than 1,000. (C) Students Rules similar to the rules of section 42(i)(3)(D) shall apply for purposes of this subsection. (D) Single-room occupancy units A unit shall not fail to be treated as a residential unit merely because such unit is a single-room occupancy unit (within the meaning of section 42 ). (E) Hold harmless for reductions in area median gross income (i) In general Any determination of area median gross income under subparagraph (B) with respect to any project for any calendar year after 2008 shall not be less than the area median gross income determined under such subparagraph with respect to such project for the calendar year preceding the calendar year for which such determination is made. (ii) Special rule for certain census changes In the case of a HUD hold harmless impacted project, the area median gross income with respect to such project for any calendar year after 2008 (hereafter in this clause referred to as the current calendar year) shall be the greater of the amount determined without regard to this clause or the sum of— (I) the area median gross income determined under the HUD hold harmless policy with respect to such project for calendar year 2008, plus (II) any increase in the area median gross income determined under subparagraph (B) (determined without regard to the HUD hold harmless policy and this subparagraph) with respect to such project for the current calendar year over the area median gross income (as so determined) with respect to such project for calendar year 2008. (iii) HUD hold harmless policy The term “HUD hold harmless policy” means the regulations under which a policy similar to the rules of clause (i) applied to prevent a change in the method of determining area median gross income from resulting in a reduction in the area median gross income determined with respect to certain projects in calendar years 2007 and 2008. (iv) HUD hold harmless impacted project The term “HUD hold harmless impacted project” means any project with respect to which area median gross income was determined under subparagraph (B) for calendar year 2007 or 2008 if such determination would have been less but for the HUD hold harmless policy.