There is always enough flexibility in interpretation to come up with a new explanation for why they are the FD&S that dismisses the 1919 teaching (which itself required quite a lot of flexibility in interpretation!).
I get the feeling that they're running up against a wall, since they are continuing to change what were/are core teachings of the organization. But when you look at those teachings, they were pretty far out there to begin with, and I don't think the rank and file know enough about them anymore. So they can probably change them and it will have relatively little impact, even though it should be a huge deal. If they could slip that overlapping generations nonsense past them, what else can they get away with?