I recently changed by Job from Company A to Company B. While I was working with company A, I had received my Labor and I-140 approvals. After I received H1B approval for additional 3 year (7, 8, 9 year), I took a full time job with company B. My new company (B) will be filling the green card after 15 month. My question is, can my old company (A) still process I485/EAD if the date becomes current? Do I need to changes my employer to Company A at that time? What should I do if the date becomes current?

Below are more details:
Labor filing (Priority date) – October 2009
I-140 approval – March 2011
3rd H1B approval – April 2011 (Valid till 2014)