The “training academy use fee fund” is created in the state treasury. All fees received by the state fire marshal for use of the firefighter training academy and its services shall be deposited into the fund; provided that no fee shall be charged the state of New Mexico or any of its agencies, instrumentalities or political subdivisions; and provided further that each contract for services in which a fee is collected shall be entered into pursuant to a business plan that has been approved by the department of finance and administration and reviewed by the legislative finance committee. Balances in the fund shall be available for appropriation to the state fire marshal for paying the operating and capital expenses of the firefighter training academy. Earnings of the fund shall be credited to the fund, and the unexpended or unencumbered balance in the fund shall not revert to any other fund.