"This most likely means you are singing the low end (normally vocalis dominant) without any balancing muscular activity from the CT and vice versa for the top."
That's along the lines of what I was thinking... But I'm puzzled because I'm not sure what's causing the imbalance. I do think I might be loading up the bottom and that causes me to carry too much weight into the top, destroying my high notes.. But I'm not sure what the dysfunction is with my high notes that's making my low notes quit.
Obviously, it's hard to say for sure without me singing for you, but I don't THINK I'm fluty on the top. If anything I'm a little on the pingy side. Before I was diagnosed as a coloratura, thank goodness, I was mis-fached as a baby spinto. So I've never had one of those very light, breezy sounds, if that is what you mean...?
In general, until I'm truly through my secondo passagio (which for me is around Ab to Bb above the staff) I feel that I have a lot of fullness and mix in the top of the staff. Singing there is no trouble, it's only when I've been singing ABOVE the staff for a while that I have this problem.
Well, thanks for your help and any further insight you can provide.
I appreciate it, every little bit helps.