If the commissioner does not act finally within a period of 90 days after a PAR is filed, or within such extended period as provided for herein, the PAR may be “deemed denied” by the petitioner for the purpose of commencing a proceeding pursuant to section 2530.1 of this Title. The commissioner may, however, grant one such extension, not to exceed 30 days, with the consent of the party filing the PAR; any further extension may only be granted with the consent of all parties to the PAR. Unless a proceeding for judicial review pursuant to article 78 of the Civil Practice Law and Rules has been commenced, the commissioner shall determine a PAR notwithstanding that such 90-day or extended period has elapsed.