I didnt read the other post but I did some "research"
How many wrinkles are in your horses lips when you put the bridle on?? The max is suppose to be 1-2
Mine had 3 O.O!!! So the next time I go up Im lowering the bit!
Sometimes even having NO wrinkles is good to they can learn to "carry" the bit rather then have it shoved up their mouth.
Think about this you stretch there mouth when you put the bit on then you stretch it even more when you ask them to whoa... I imagine it gets painful.
Just my $0.02 :)