(a) The approval by the municipal governing body of the budget under this subchapter shall, for the purposes of the budget from time to time amount to an appropriation of funds which are lawfully applicable to the items therein contained.
(b) The governing body may alter or revise the budget and unpledged funds appropriated by the governing body for any purpose may be subsequently, by action of the governing body, appropriated to another purpose, subject to the following exceptions:
(1) Funds resulting from taxes levied under statutes or ordinances for specific purposes may not be diverted to another purpose;
(2) Appropriated funds may not be diverted to another purpose where any creditor of the municipality would be prejudiced thereby.