Section 29C. Except as otherwise provided for by law, the general court or any agency of the executive or judicial branches of the government which acquires property or services from a commercial vendor, including both profit and not for profit corporations, excluding state employees, recipients of public assistance, cities and towns and other municipal forms of government, but which does not make full payment by the required payment date for each such complete and appropriate item of property or service delivered under an applicable purchase order contract, shall be liable for late penalty interest to said commercial vendor on the amount which is due under the following provisions:

(a) that the required payment date shall be the date on which payment is due under the terms of the contract for the provision of said property or services; or, if a specific date on which payment is due is not established by contract, not more than 45 days after receipt of a properly authorized, approved and submitted invoice for the amount of payment due, unless the usual and customary time for payment is longer;

(b) that the late penalty interest provided for under this section shall be computed at a rate to be set semi-annually by the secretary of administration and finance on January 1 and July 1 of each year; provided, however, that said rate shall be equal to the discount rate charged on said dates by the Federal Reserve Bank of Boston;

(c) that this section shall apply to any late penalty interest which may be due under this section;

(d) that this section shall not apply to the delivery of any property or services made at the beginning of any fiscal year unless a general appropriation act is in effect for said fiscal year. Upon the passage of a general appropriation act, a required payment date may be set or the 45 day period as provided in clause (a) may be commenced;

(e) that, within 15 days after the date on which any invoice is received, state agencies notify any such commercial vendors of any defect or impropriety in such invoice which would prevent the running of the time period.

Any state agency required to pay interest under this section shall pay any amount required out of funds appropriated for the administration or operation of the program for which the interest was incurred.

The secretary of administration and finance shall, not more than 60 days after the conclusion of each fiscal year, file with the house and senate committees on ways and means a summary report on any interest penalties made under this section during the preceding fiscal year. Such report shall include the number, amounts, frequency of interest penalty payments and reasons such interest payments were made, summarized by state agency and secretariat, where applicable.

A copy of rules and regulations promulgated under this section, or any amendment or repeal of any such rules and regulations, shall be filed with the house and senate committees on ways and means at least 30 days prior to implementation.