Okla. Stat. tit. 43A, § 43A-4-204: Time of payment - Statement of sum due

The cost of the care and treatment of the consumer shall be paid

monthly unless the Commissioner of Mental Health and Substance Abuse

Services and any person agreeing to make the payments may arrange

for quarterly or semiannual payments. The executive director of a

facility within the Department of Mental Health and Substance Abuse

Services in which a consumer is held shall issue a statement of the

sum that is due to all persons who are liable for the care and

treatment of the consumer, but failure to send or receive this

statement shall not affect the liability of a person who is

otherwise liable for the care and treatment of the consumer.