Okla. Stat. tit. 19, § 19-180.59: County assessor's certificate controlling as to

valuations.

The gross assessed total tangible property valuation for ad

valorem tax purposes in each county, or service-ability factor,

shall be determined from the county assessor's certificate of such

valuations as filed with the excise board of the county for the

purpose of computation of ad valorem tax levies of each year, and no

subsequent amendments thereto to effect an increase or decrease in

such valuations shall have any effect for such year whatsoever.