Are you going to revert back to veg after transplant?
If not, I'd say leave them this time, and think about transplanting a few weeks earlier next time.

When you transplant, it can sometimes take a couple of days to a couple of weeks for her to recover. Don't really want her to start the bloom cycle suffering from root abuse or broken stems due to manhandling.
Also, since she has been in flower the past couple of weeks, you'll want to control her nutes. If the soil you'll have to add contains too much nitrogen, can freak the ladies out. (additional internode stretch tword top of colas, occational male parts...)

There are transplant additives but I don't use 'em any more. I just never saw a difference between using it, and not using it.