Section 2. Subject to appropriation, for each fiscal year commencing with fiscal year 2008, any city or town that has established 1 or more smart growth zoning districts shall receive smart growth school cost reimbursement from the commonwealth. This reimbursement shall be equal to the positive difference, if any, between: (i) total education cost for eligible students, and (ii) the sum of local smart growth revenues for education plus additional chapter 70 aid. The department of education shall add the smart growth school cost reimbursement amounts to each district's required net school spending, as defined in chapter 70. For purposes of the net school spending calculation, the department shall allocate a municipality's smart growth school cost reimbursement among the districts to which it belongs in proportion to the number of eligible students from the municipality attending each district.