Hard to say. It's always better for the canopy to be the same height, and anything lower is at a risk of being lower quality at harvest after receiving lower-intensity light. But if you bring the outer colas down you'll take up more floor space.
Most people would advise you to cut the lower colas that will never catch up. But I hate having an open space in the middle of the plant. I have two plants right now in the same situation (one is close to harvest). And I just left them. If photons are getting absorbed by dirt in the pot they're not being used.
I know conventional wisdom says that your other buds will be smaller. I'm not so sure, especially if they're catching photons that would be wasted. Besides, if nothing else, you can save those smaller buds for the dry times. Or convert them to hash (which is my plan).
But like I said, I've only been growing for a couple of years.
I was reading recently about some traditional landrace growers that would put buds from the top 1/2 in the 'primo' pile and the others in the 'regular' pile. That's also my plan.