(2) On oil or gas sold at the time of production, the gross production tax shall be paid by the purchaser, and the purchaser shall and is authorized to deduct in making settlements with the producer or royalty owner, the amount of tax so paid. In the event oil on which the gross production tax becomes due is not sold at the time of production but is retained or used by the producer, the tax on the oil not so sold shall be paid by the producer, including the tax due on royalty oil not sold. In settlement with the royalty owner, the producer shall have the right to deduct the amount of the tax so paid on royalty oil or to deduct royalty oil equivalent in value at the time the tax becomes due with the amount of the tax paid.
(3) The amount of gas produced and used for fuel or otherwise used in the operation of any lease or premises in the drilling for or production of oil or gas, or for repressuring, shall not be considered for the purpose of this chapter as gas actually produced and saved.
(4) When oil or gas is sold at a sale price that does not represent the cash price prevailing for oil or gas of like kind, character or quality in the field from which such product is produced, the department may require the tax to be paid upon the basis of the prevailing cash price then being paid at the time of production in the field for oil, or gas of like kind, quality and character. [1981 c.889 §5]