(a) Reasonable deductible or copayment plans, or both, after approval by the Insurance Commissioner, may be applied to benefits paid to or on behalf of patients during the course of alcohol or other drug abuse or dependency treatment. In the first instance or course of treatment, no deductible or copayment shall be less favorable than those applied to similar classes or categories of treatment for physical illness generally in each policy.

(b) In the first instance or course of treatment under a prospective payment plan, no deductible or copayment shall be less favorable than those applied to similar classes or categories of treatment for physical illness generally in each policy.