H4 EAD for spouse using I-140 approved through different employer

[etMurugan]

Its regarding H4 EAD.  My I-140 got approved 8 months back through my current employer and I recently got a full-time position. The new employer is in the process of filling my H1B and H4 extension for dependents. Per Jan 17 2017 rule, if the person is stayed more than 180 days after I-140 approved, the employer cannot revoke their I-140.

So, I would like to know whether I can request my new employer to file a H4 EAD for my spouse based on my current approved I1-40 along with  extension. if possible, how long would it take to approve H4 EAD and my new employer is filling in premium process.