Yup, one less round. But DPS should be higher.
As long as you have good tanks that's the only way I would conceive doing a heroic ambershaper pug. Get as many stacks as possible on the boss and nuke him right before a scalpel with all CDs. This way you don't have to do anything fancy in P2 aside from what you would normally do, and you can ignore the P3 mechanic (which is really not a good mechanic.)
I am the lucid dream
Uulwi ifis halahs gag erh'ongg w'ssh