Section 20: Two commissioners not to adjudicate on same instrument.

(20) Any person, other than a public officer in the exercise of his official duties who, after an instrument has been submitted to a commissioner for his opinion as to the amount of duty with which the instrument is chargeable, subsequently submits the same instrument to a different commissioner for an expression of his opinion as to the amount of duty with which the instrument is chargeable shall be guilty of an offence and shall be liable on conviction to a fine of twenty naira.