I have no advice, except to say that when I moved my tomato seedlings from six-in-a-pot to five-in-the-ground, one-in-the-pot, one of the transplanted ones went VROOM, while the rest lagged. So, transplanting can't hurt, and might help?

But, yeah, I've got six tomato seedlings started at the same time, and only one of them's got flowers yet. Sometimes, plants are just weird.