Even ignoring opportunity cost of a better ability aside, refreshing early at most grants you 30% more damage.

Ballpark means if you are clipping longer than 10 seconds, its not worth it. I would go ahead and say if you're clipping more than 6 seconds, its not worth it.

You can view dots as merely a big nuke with a CD.

In other news, this is exactly the type of scenario a simulator would solve.

Also also, its definitely not worth it because the opportunity cost is a TTT combo.