Tanks can take far more than 2 if they're careful to keep the right CDs up for the last phase. It looks like you're using sin/jug as your tanks? If you want to make the last phase last a long time, make sure your tanks have at least their pull (for the sin), AOE taunts, and reflect/shroud up.
A sin can take 3 balls by finding 2 that are close together and pulling a third in, AOE taunting, shrouding, and running through them all. If you're really quick you can sometimes get a 4th in shroud by single target taunting and sprinting to it. That sets you up to take a 4th (or 5th, if you got to shroud 4) by stunning it and waiting on your single target taunt to come back up so you can take it either with blackout or no DCD, depending on how high HP you are, or just suiciding it if it's in a bad spot and you just want to blow it up (If you're smart with CDs you can get far more than this as a sin, you have a ton of tools).
A jug can't get quite as many, because they can't pull, but AOE taunting 2 into reflect + a leap and single target taunt on a 3rd before reflect wears off is an easy 3, and between choke and backhand you can control a 4th long enough to pop it safely even if you have no other CDs up.
Having your tanks up eating more balls at the end will help give a bunch more DPS uptime on the boss and cut into that 8% quite a bit.