Matt, the episode in which Kramer assumes the role of the movie phone guy, is episode #112 'The Pool Guy' in season 7, it originally aired on 11/16/95.
That's also the one in which George's 'world's are colliding' because Susan is starting to invade "independant George's" space with the gang.
It seems like they are alternating between 2 releases at a time and then one release at a time. Seaons 1 & 2 (as a set were released with Season 3. Then Season 4 arrived by it's lonesome. Now 5 & 6 are coming. I'm expecting #7 alone and then 8 & 9 together.