So what your saying is use MBAM whenever it procs? even if its after the first AB? If so then you will loose dps not gain. there's only 2 rotations:
1: The usual ABx4 followed by MBAM, if no proc then depending on mana AB a few more untill or maybe you have to move in which case ABr. Either way this is the standard rot.
2: You have very high Haste (1k~), Spell Power (3.2k+ unbuffed) and 2pt10 (obviously) so you use ABx3--->MBAM (if you get lucky enough). This way you should nearly 100% up time on 2pt10 12% haste buff making ABx3 MBAM as good if not better depending on player skill (chain casting) + its much more mana efficient, therefor you wont need to Evo.
This is exclusive with BL and IV phases.
So imo its something like this. There really isn't any other rotation for arcane.
Ps: number 2 rotation is in an ideal world where you would proc MBAM before the 3rd AB.