Still seems strange there are so many versions.... the original, the one with a longer base (I guess it is) and the totally flat one. And I don't think we've seen a new car with the newest ones. But they do look like the best 'engineered' answer so far!
This is typical. Just about every part of the car has had multiple revisions. As another example, I've been trying to get a tow hitch cover which was missing at delivery. They've ordered several different revisions of it and none of them fit!