@exolithus:
potency was: 13.3~ (non RS) 16 (rs). As this is the best DOT damage skill the benefit applied follows less with the other dots. a total of 9ish potency benefit for 20 seconds with all 3 dots. On the other hand CS is giving you a benefit of 10% over 100% of the time vs RS giving you 20% 1/9th of the time [180s recast, duration 20s]) so the benefit on potency is weighted toward the class with CS and not RS. We ignored to give SMN the benefit of the doubt...

ED returns 50% of damage dealt rather than cost mana: 266 for me x3)
Aero requires mana (106 per cast. for 1 min 3 casts so 318).
In the end, you return 480 after subtracting aero cost. so my premise 'and you get mana back' is correct 100%.

Aero is a dot, it costs you 1 GCD per cast (18s) in your rotation. for giggles lets give the SMN +3 rune IIs (5.3 potency/sec over the 60s window) which will still put us under potency aero/ED combo.