Section 19. Municipalities and school districts shall notify the authority no later than 14 days before refinancing any bond for which the municipality or district will receive state reimbursement under chapter 645 of the acts of 1948 or other law. The authority shall reimburse municipalities or districts at the actual interest rate obtained. The authority shall encourage municipalities and school districts to refinance any bond for which the municipality or district will receive state reimbursement where the refinancing would result in savings for the commonwealth or the municipality or school district and where the refinancing is otherwise in accordance with the law.