This answer made me wonder if two or more season pass for one show but different seasons could be set up, so I tried by first creating a season pass for "A Show" and on the DVR using advanced specifying SeasonNumber == 1 and renaming it to "A Show S1".
The DVR software does not allow me to directly create a second season pass for the same show, but by creating a season pass for a different show, and then changing the name to "A Show S2" and deleting the "wrong" SeriesID and adding the SeriesID == X for my intended show, and adding SeasonNumber == 2, it actually scheduled recording of all season 1 and 2 shows currently set to air.
Is this a usable workaround that will not cause unintended problems for the DVR software?