What happens to years remaining on H1B after working on EAD

[ektanit]

Hi People , I need some advise.
I hold a EAD card (valid till Oct Oct 08) and H1b ( valid till Jan 2011) with employer A. My spouse can only be on EAD, he is a derivative on my Green card application and has completed 6 years of his H1B.
I plan to join employer B on EAD.
1. How many days do we have to file AC21. Can I file after 6 months.
2. Can I re-join employer A on EAD before filing AC21
3. Can I re-join employer A on H1B before filing AC21.If yes, what will happen to the EAD for me and my spouse.
4. Once I come on EAD, can I come back on H1B ( If for any reason my 485 is denied )or I will be subjected to the annual quota.

[txh1b]

1. No stipulated time. The sooner the better so that USCIS can send communication to new employer/lawyer. There is no mandatory requirement to file AC21 either.

2. Sure.

3. Sure. Nothing happens to EAD. The EAD is given o the beneficiary and is independent of the employer.

4. Possible if you have any time left.