qualified basis of such building as of the close of the 1st year of the credit period, the applicable percentage which shall apply under subsection (a) for the taxable year to such excess shall be the percentage equal to 2/3 of the applicable percentage which (after the application of subsection (h)) would but for this paragraph apply to such basis. (B) 1st year computation applies A rule similar to the rule of paragraph (2)(A) shall apply to any increase in qualified basis to which subparagraph (A) applies for the 1st year of such increase. (4) Dispositions of property If a building (or an interest therein) is disposed of during any year for which credit is allowable under subsection (a), such credit shall be allocated between the parties on the basis of the number of days during such year the building (or interest) was held by each. (5) Credit period for existing buildings not to begin before rehabilitation credit allowed (A) In general The credit period for an existing building shall not begin before the 1st taxable year of the credit period for rehabilitation expenditures with respect to the building. (B) Acquisition credit allowed for certain buildings not allowed a rehabilitation credit (i) In general In the case of a building described in clause (ii)— (I) subsection (d)(2)(B)(iv) shall not apply, and (II) the credit period for such building shall not begin before the taxable year which would be the 1st taxable year of the credit period for rehabilitation expenditures with respect to the building under the modifications described in clause (ii)(II). (ii) Building described A building is described in this clause if— (I) a waiver is granted under subsection (d)(4) with respect to the acquisition of the building, and (II) a credit would be allowed for rehabilitation expenditures with respect to such building if subsection (e)(3)(A)(ii)(I) did not apply and if the dollar amount in effect under subsection (e)(3)(A)(ii)(II) were two-thirds of such amount. (g) Qualified middle-Income housing project For purposes