0.5 sec Totem + 1.5 sec Storm Field + 1 sec Nebthu + 1 sec Call Lightning = ~4 seconds
(not sure how you get 20 sec out of this calculation but if you stop and do nothing after one cast it’s obvious that it takes more time)
Storm Field gets one tick after activating ~650 damage
Nebthu the same ~ 700 damage
Call lightning does damage after cast finished ~1050 damage
Totem should have damaged in that time at least twice too ~350 damage
So we are at roughly 2750 damage in a matter of approximately 5 seconds and keep in mind that this is just to start everything up. My ToS got epic unchained , T4 gear and one T5 item so I would say it’s below average.
Also: Fangs of set might be not that useful in PvP due to too high hitrating but I got no clue about that but since bosses in the game got the same hitrating for years the 90% miss-chance still works completely fine.
I hope any moderator can ban this guy, trolling on guides isn’t great as people who try to find useful information can get confused by these posts.