FIGURED IT OUT!!!!!!!!! YIPPEEE!!! I kept retracing my steps from what happened in the Stone Cold Crazy solo 3 jump to 95%, and used the clues from Derrick's information and wording to do it.
Thanks derrick if you were going to tell us:
*I'm not sure if all these steps are necessary. Feel free to shorten the method after testing.
Leveler Bug: (How to level stuff to 100% the cheap way)
STEP 1. Go to the section of the song you want to level and open it in the Leveler.
STEP 2. Once you're in the song, SET THE MASTERY DOWN to an easier % (I used 4% for the SSB bridge), and play it until it says "Level Up!"
(I'm not sure if failing here would affect the bug-- in my testing I made sure to pass the first time.)
STEP 3. RIGHT AS IT SAYS "LEVEL UP!" (you hear the grinding wheels and see the message), PAUSE IT and set the mastery to 100%.
STEP 4. Fail the section on purpose once, and PAUSE IT as it says "too many notes missed!!!" After pausing, choose "end now."
STEP 5. After you get the message "you failed to achieve the mastery bla bla bla", and the game saves, choose "Play again!"
STEP 6. While still in the tuning screen, pause and select "end now".
STEP 7. The game will say "you failed to achieve mastery at bla bla bla%." Press OK, let it save, then choose "continue journey." You'll be back at the event setlist.
STEP 8. Hit Start to bring up the main menu. Go to options and set the difficulty to "highest achieved."
STEP 9. Go back to the section, it should be fully leveled.
In spite of my feverish testing, I feel everyone deserves to know the information. It's not fair to play some ultimate judge of morality that determines information other people should or should not be allowed to know. Everyone can help each other-- share the information they find so we all benefit.
It's wrong to tell someone you know what's best for them; you can only know what's truly best for yourself. I believe the right thing to do is let people make their own choices, no matter how dangerous or potentially bad the choices could be-- they still have a right to have them.
-- *End speech* --
I hope this serves as a stepping stone in the community for everyone to help each other have a better playing experience.