If they are with this fast pace maybe they'll go until volume 6 that was the best of Oregairu until now. But even if they go with 2 episodes per volume we'll have:
Vol3 = Episodes 6/7
Vol4 = Episodes 8/9
Vol5 = Episodes 10/11
Vol6 = Episodes 12/13
Which would be a huge letdown, after all the volume 6 needs at least 3 episodes considering there are 350 pages... To finish the season in the volume 5 will be a little strange, but maybe it'll be a good sign for a season 2
