For my 70-271 I was doing 1-2 hours a day.
For my 70-272 I was doing 2-3 hours a day.
For my 70-621 I'm hitting 4-5 hours a day, purely due to the content of the exam (that it's a combination of two, 620 & 622).
I'm in the same boat as you. I want to get everything done quick sharp because there's no point in waiting around and I can progress quite easily given I'm qualified enough.
There was no gap between 272 and 621 though, so I might take a week no revision once (if) I pass.
All booked up for the 13th
So yeah... 20 hours + for me.