That's kinda the same problem with WKRP. So much great music that's hard to get the rights for. But what do you expect for a show about a rock radio station?
Is that why they stopped showing WKRP reruns? Antenna TV used to show it pretty regularly, up until a few years ago.
I've noticed that sometimes they'll substitute a different song, in later releases as well. For instance, there's an episode of "Mama's Family" called "Obscene Caller", where Naomi keeps getting harassed on the phone. At one point the family tried to record the caller. Vint gets a boom box, they hold the receiver up to it, but then Vint presses a wrong button and you hear Willie Nelson singing "On the Road Again."
On the DVD set, when Vint presses the wrong button, it plays some other hokey country song I don't even recognize. Oddly though, when I catch it on tv reruns (MeTV and Logo both run it) and it's still Willie Nelson's "On the Road Again."
So, maybe whomever handles the distribution of the package for broadcast was able to get the rights to "On the Road Again", but Star Vista Media, who put out the DVD set, couldn't?
For some reason, I'm thinking there's two different versions of "National Lampoon's Vacation" as well. One of them has "I'm So Excited" by the Pointer Sisters playing every time the Griswolds come across Kristie Brinkley in the Ferrari. But I could swear there's another version, where they only use that one song that was playing when they were at the rest area, and Clark ate the sandwich that the dog peed on.