i am not mass pull tank

[Pells]

And that's the reality, for example in Xepalothl. It's literally 30% faster. At least, because finite ammount of time/ressource restricted actions and CDs not counted in.
[E.g. you can have 2-3 Aetherflow/DWT/deathflare in the first 80-110s max, either on 4 groups (one group won't get hit by a deathflare) or on 2 (you even saved 3 stacks/DWT/etc. for the Boss now)]

Literally 30% faster. So what you're saying is if you do single pulls and it takes 20 minutes... if you mass pull it'll only take 70% of that time (14 minutes). A net savings of 6 minutes.

... Differences was 5-7 minutes...

I'm not seeing why you're arguing against Brill.

If the runs are taking 30-40 minutes, it has very little to do with how the tank is pulling.