It seems pretty clear to me that something that airs a year later is a new season. Add to that the fact that it's $22... Did you really think that got you 16 HD episodes of a very popular currently airing show? I get that the wording was confusing, but how about a little common sense?
I wouldn't say it's 100% clear what a "season" is, but Apple offered (and still offers) Season 5, consisting of 8 episodes and various bonus material, and I suppose you will get exactly the 8 episodes and the bonus material for your money. And when it was first sold, it was indeed the complete "Season 5". I don't think Apple can be reasonably blamed if the movie company then makes more episodes and also calls them "Season 5". They could have made some more episodes following the ones in Season 1 and called it "Season 1".