Dear Saurabh, Currently I am working for profit consultancy. Now, I need to join a non-profit organization. Later if I come back onto profit consultancy, please let me know if the non-profit working time will acumulates as part of my whole 6 year?
The 6 year clock includes all time working on H1-B. The only advantage of cap-exempt non-profit is that if you use up the 6 years, spend a year outside the US, then you can get a new 6 years on H1-B at the cap-exempt non-profit without worrying about a lottery.
Ask your lawyer though.