so here's the exact data on 1b after some brief testing
1B TC's between frames 4 and 9.
1B TC's really early but loses it's frames long before the attack hits
earliest TC I can find is on frame 4
Aeon 1 v. Aeon 2
Aeon 1 does 1B (BS -9), Aeon 2 blocks
Aeon 2 does AA (i13 - 9 frames = 4 frame high)
Aeon 1 does 1B, ducks and CH's
Latest TC is 9 frames
Aeon 1 v. Aeon 2
Aeon 1 does 6A (BS -4)
Aeon 2 does AA (i13 - 4 frames = 9 frame high)
Aeon 1 does 1B, ducks and CH's
Aeon 1 v. Aeon 2
Aeon 2 does B+K (BS +3)
Aeon 2 does AA (i13 - 3 frames = 10 frame high)
Aeon 1 does 1B, but gets hit
Intrestingly, 1B BE DOES duck in the situation above, and ducks when B+K is replaced with 1B BE, so it ducks at least till frame 11. Did not test exactly when it stops ducking, too lazy.
For the record, 4B+K ducks later then 1B, but retains it's TC for a hella long time, TJ's later, and can also duck mids. It starts ducking at frame 9, if i remember correctly.
So, long story short, 1B is more suited as a anti-high panic button and 4b+k/1b be are pressure anti-high buttons. well, 4b+k is anti a lot of stuff.