For the 1991-1992 school year, each intermediate unit, in the aggregate, including the intermediate unit and its member school districts, shall receive at least a three and five-tenths percent (3.5%) increase in the aggregate revenue for special education over the aggregate cash amount available from the Commonwealth for special education during the 1990-1991 school year. The intermediate unit shall meet with its constituent school districts to develop a plan for the expenditure or distribution of the funds provided by this section for the purpose of the provision of special education programs and services. These funds may not be expended or distributed by the intermediate unit until a majority of the boards of directors of the constituent school districts have approved such expenditures or distribution. If the amount received under the provisions of this section is less than ten thousand dollars ($10,000), such amount may be retained by the intermediate unit for the purpose of providing special education programs or services without the approval of its constituent school districts. For the purpose of computing the revenue available for the guarantee in this section, the Commonwealth shall include funds allocated pursuant to sections 2509(f) and 2509.5(b),¹ plus an amount equal to three times the school district payment to the Commonwealth pursuant to section 2509.1(b)² and the funds allocated pursuant to sections 2509.1(c), (d) and (f) and 2509.6.³