State agency contracts for services shall be subject to the following requirements:
(1) Payments shall be made when contractual deliverables are received or in accordance with specific contractual terms and conditions;
(2) State agencies shall not enter into contracts for services with an unspecified or unlimited duration, and no contract for services shall be amended to extend the duration of the contract for a period of more than fifty percent of the initial contract term. Following the adoption of any amendment to extend the contract for a period of fifty percent or less of the initial contract term, no further extensions of the original contract shall be permitted. This subdivision does not prohibit the exercise of any renewal option expressly provided in the original contract;
(3) State agencies shall not structure contracts for services to avoid any of the requirements of sections 73-501 to 73-510; and
(4) State agencies shall not enter into contracts for services in excess of fifteen million dollars unless the state agency has complied with section 73-510.