I worked for company A for almost two years. They applied labor and it was approved and filed I140.

I moved to company B on H1. After two months I140 approved through A.

My priority date became current and company A filed I 485 though I am working for company B.

I am still working with company B.

4 months back received RFE on EVL, company A responded.

3 months back my I485 transferred to National Benefits Center.

Recently interview letter received but later cancelled(no reason mentioned), waiting for another letter.

My question is:

1. Can I apply AC21 from company B? or do I need to work 6 months for company A to qualify for AC21?