A Surely All-But-Pointless Mythbusters Observation

A while ago, I got a DVD collection of "Mythbusters" episodes that had thirteen episodes split up among four discs. Pleased to have an official and easily available collection of this show for my own, I picked up on the news of another collection and got it, to find that its thirteen episodes (one an extended-length special) were split up among three discs. Then, I got a third collection in the series, interested to hear that it had the show's three very first episodes included... and then discovered that it had twelve episodes, split up among two discs. I'm starting to wonder if the producers of the collection are trying to see how much they can compress the video before it turns into mush.