Each milk dealer shall pay for all milk purchased or received from another milk dealer on or before the 20th day of the month following the month in which the milk was purchased or received. If the commissioner fixes an earlier final date for payment by a milk dealer to a cooperative association of producers which is also a milk dealer with respect to milk subject to regulation under a marketing order promulgated pursuant to the provisions of section 258-m or 258-n of the Agriculture and Markets Law, such earlier date of payment shall be effective under this Part for milk purchased from such cooperative.