When to switch is always a preference of the grower. Thats YOU. The longer you veg, the bigger your plant should be overall. Light penetration is of course an issue for anybody but you have a 400 and possibly a 600 watt light so that shouldnt be a problem.
Honestly, its your call, flip it now and it finishes all that much sooner. Wait it out some more and you should have a bigger plant.
Some people just need some stash quick plain and simple
Nothing wrong with that either. If thats the case.....say so.
Right now I'm in the same boat. Mine have been vegging for 7 weeks now and its driving me nuts. I wanna flip 'em and get on with it, but at the same time I took the time to LST them ans that takes time, and the idea is I want to maximize the yield so I'm hangin on awile longer.
.....But I got a dozen or so jars on the shelf
That is somewhat helpful.