Level Grades

I'm trying to figure something out involving level grades.
I may have got the most of it, but I want to clarify.

In a 1-byte configuration, 00 00 00 00:

*when the bit of 1 is 1, the level has been first accessed, but not yet cleared.
*when the bit of 2 is 1, the level has been cleared for the first time in regular mode.

Now the rest seems odd to me, but my guesses:

*the bit of 4 is 1, means that the Emerald Token has been collected for the first time?
(Biggest assumption for 2.1.x is that there's only one token per Act...)
*the bit of 8 is 1, means the level was cleared on Ultimate Mode?
*the bit of 16 is 1, means it was cleared on Record Attack for the first time?

Is there anything else I need to know for the bits for 32, 64, and 128?

Examples:
Greenflower Act 1 -- 00 01 00 11 -- Beat the level in both Regular & Record Attack modes, but hasn't found the Emerald Token, likewise cleared it on Ultimate Mode.
Grade Value is 19.
Egg Rock Act 2 -- 00 00 01 11 -- Only cleared it regularly with the Emerald Token collected.
Grade Value is 7.
Act 3's, since no Emerald Token exists, it cannot have the '4' bit as 1; max Grade Value is only 27 (unless someone helps out).

Good to know.

So 16 is obtaining a Perfect Bonus on said level, hmm? I wonder why I'm obtaining it upon clearing Record Attack then.

Max is 31. Gotcha. Now I don't need to worry anymore, thanks.