Hey Texas,
Roots do continue to grow at a slower rate then veg yet do still grow. Assuming your current problem is roots and not nutes. I would look at it like this If you are rootbound your growth is already guaranteed to be stunted and yield will suffer. Depending how much time you have left to flower say 3-4 weeks or more your running the risk of all kinds of other problems that equate to sickly or dead plants. Or you replant them sure it could cause stress and delay growth bfor a bit but once those roots stretch and can start utilizing the nutes and get that Xylom flowing to your buds seems worth it in a damned if you do damned if you dont situation. If your scared to do a more traditional re-pot Buddy and me came up with somthing we call LSP (Low Stress Potting lol trade mark chillnburn1* Actually did it because of a very similar situation. Cant tell what kind of pot shes in , but sure this would work with any plastic or best with a grow bag. Basically what we did is the day after a watering when your soil is damp not wet not dry, use your hands to press against the sides in a rolling motion to loosen the medium around the sides then get your larger pot or bag ready that your transplanting by putting a pot or object the size of your current pot in order to make a perfect casting after you add all your medium around your fake pot or whatever I dont suggest doing this with the pot that its in since its large and accidents happen! Anyways once you have a casting for your plant take it and make sure you roll again just like a normal re-pot. Now heres the part you need a buddy have your buddy hold the plasticmedium pot by grabbing north and south on the bucket and with some strength pull hands together so bucket creates a oval shape freeing two sides away from roots and medium. At this point you simply come in with a brand new sterilized razor preferably like a drywall blade and cut either the bottom out if possible or slowly plug large holes around the side basically turn it into a netty pot. Place the newly swiss cheesed bucket or bag in new pot and there you go. Two things be super careful obviously not to cut yourself or the roots and try not to leave any sharp corners when you water dont water the inside pot since you did this the day before but water the shit out of the outer medium so the roots stretch for it as that pot dries out. Normal watering after two feeds.