As noted above, Black Belt destroys Twilight before even taking AF3+2 procs into account. Going from 4/5 to 5/5 AF3+2 is a 2% increase (3% to 5%) to proc an additional kick, not affected by DA/TA. In essence, it's +2% DA in a separate term which is not affected by the (semantics, I know) decreasing returns of standard DA.

In essence, putting absolutely everything in the favor of Twilight and only looking at attacks per round, you have:

(Triple Attack rate) + (Double Attack) + (Kick Attacks) + (Minimum Punches) + (AF3+2 proc)

(0.18)(2) + (1 - 0.18)(0.20) + (0.15) + 2 = .36 + .164 + .15 + 2 + 0.03= 2.704 attacks per round with Twilight

vs

(0.18)(2) + (1 - 0.18)(0.18) + (0.15) + 2 + 0.05 = .36 + .1476 + 0.15 + 2 + 0.05 = 2.7076 attacks per round with 5/5 AF3+2.

You're not getting more DA procs with Twilight and Fumas. You're getting fewer. And your additional attacks with AF3+2 do *More Damage* than your punches because you're wearing D+45 shoes.

I'm beating a dead horse but I figured it was worth pointing out that Twilight doesn't even have an edge in attacks per round either. Seriously, there is no reason at all for any MNK to not use a Black or Brown belt.