How to work 5 hours per day with 12 hours velocity | Mikhail Bakhrakh at BA and ProdM Days

Without intrigue, there is no sense to start a talk :)
What if I will tell you that I can painlessly shift my work time within a range from 100 % to 10% workload per day without any loss in productivity for a task, milestone, project, product, community, my children?
What if I will tell you that for the last 5 years I have been working average not more than 5-6 hours per day with at least 12 hours velocity?
What if I will tell you that almost any Business analysis (and not only) task you evaluate in X hours I will complete within X-30% (-50% - 70%) hours?
What if I will tell you that there is and I can shyarre the secret recipe of such productivity - do you believe?
Here the just tiny example and obvious at the first look, but...do you really follow it in your everyday life?