Hi Ginnu,
This is an interesting topic, saving time on H1 by switching to EAD. And I will make you wiser and let you know that if you switch to EAD, you DO save the remaining time on H1.

Please read the last paragraph here:
http://www.immihelp.com/gc/aos/eadap_h1.html
I Reporoduce it below :
Some H-1B professionals use EAD(and terminate H1B) on purpose to save H-1B time so that if something happens with the current employer, they be able to pick up the remaining period of the 6-year H-1B limit through another H-1B approval with the new employer.