(1) Each employer-sponsored group policy for comprehensive health insurance which is entered into, or renewed, on or after twelve months after July 23, 1989, shall include coverage for neurodevelopmental therapies for covered individuals age six and under.

(2) Benefits provided under this section shall cover the services of those authorized to deliver occupational therapy, speech therapy, and physical therapy. Benefits shall be payable only where the services have been delivered pursuant to the referral and periodic review of a holder of a license issued pursuant to chapter 18.71 or 18.57 RCW or where covered services have been rendered by such licensee. Nothing in this section shall prohibit an insurer from negotiating rates with qualified providers.

(3) Benefits provided under this section shall be for medically necessary services as determined by the insurer. Benefits shall be payable for services for the maintenance of an insured in cases where significant deterioration in the patient's condition would result without the service. Benefits shall be payable to restore and improve function.

(4) It is the intent of this section that employers purchasing comprehensive health insurance, including the benefits required by this section, together with the insurer, retain authority to design and employ utilization and cost controls. Therefore, benefits delivered under this section may be subject to contractual provisions regarding deductible amounts and/or copayments established by the employer purchasing insurance and the insurer. Benefits provided under this section may be subject to standard waiting periods for preexisting conditions, and may be subject to the submission of written treatment plans.

(5) In recognition of the intent expressed in subsection (4) of this section, benefits provided under this section may be subject to contractual provisions establishing annual and/or lifetime benefit limits. Such limits may define the total dollar benefits available or may limit the number of services delivered as agreed by the employer purchasing insurance and the insurer.