(a) The minimum standards prescribed by the Division of Aging, Adult, and Behavioral Health Services of the Department of Human Services for purchases by community mental health centers, so far as practicable, shall be comparable to the limits set for small purchases under the purchasing procedures established by the State Procurement Director and shall require competitive bidding for purchases exceeding those limits.
(b) However, the purchasing standards established by the division shall not require competitive bids for contracts for professional services in the health, medical, legal, and accounting fields, but shall require the contract entered into by a center to be approved by the chief executive officer and the governing board of the center.
(c) The standards promulgated by the department shall also require the center to maintain adequate documentation concerning procedures used and the justification for the awarding of the professional contracts.