I have Rockii seedlings grown from APS seed and a member here, they germinated the same as the others and didn't seem to grow any slower. None of mine have made it to bloom yet though. The seedlings in the OP were young, haven't bloomed yet. If I were selling and there was no different effort and unproven blooms I'd sell for the same price. Actually I'd probably never sell if they haven't bloomed, I'd be too curious about what the flowers would look like!
I've not tried grafting at all so have no clue about that yet!
