How practical is ACB for money saving purpose?

I don't remember perma-immobilized mobs. I actually timed a "perma stunned" Dual Ghost Pirate, and it turned out to be roughly 2.4 minutes.

 7 elder wraiths

These were stunned at least for half the duration of the acc pill, you can see it's the same 7. I know some of them were stunned longer than that cause it was early when I came in the map. So probably more like 8-9 minutes. I ended up leaving and re-entering every time I got more than 3-4 stuck like that from then on cause it kinda ruined the spawn rate.