All members of the same controlled group of corporations, as defined in 26 U.S.C. §41(f), and all entities under common control, whether incorporated or not, shall be treated as a single taxpayer for purposes of the tax credit. The credit allowable to each member shall be determined by multiplying the total credits certified by the Department for the controlled group by a fraction: The numerator of which is the Maryland qualified research and development expenses incurred by the separate member; and The denominator of which is the total Maryland qualified research and development expenses incurred by all members of the controlled group. The computation of the credit amount shall include all of the qualified research and development expenses of an acquired, consolidated, restructured, or merged entity.