also be careful of those roots. They're not going to recover as quickly as they would while in veg growth. I actually have to put one of the girls i had in a one gallon into a bigger pot tomorrow. Just didn't have room before I cut down some males.
I think it would be totally fine as long as you do not disturb the root ball. It should be done early in bud though when the plants are still stretching as the roots will not use the extra soil if done late. I believe root growth almost stops when the stretch stops. I could be wrong but I remember reading this somewhere.