Final AC21 updates

[rahulsi81]

Current Scenario : My 140 was approved was not withdrawn by employer A untill 180days.
I joined employer B and got H1b approval till my 6yrs validity.
But Employer B did not file for 140/PERM.Employer A has withdrawn 140.

Now Can i move to Employer C ? Will i get H1b transfer approved and extenstion beyond 6 yrs , by using Employer A withrawn 140 ?

Final AC21 updates(https://www.govinfo.gov/content/pkg/FR-2016-11-18/pdf/2016-27540.pdf) in 2016/17 has few updated provisions in
 8 CFR 205.1(a)(3)(iii)(C) and (D) AND  8 CFR 204.5(e)(2).From these updates it seems possible , but not a atornrey so need your help to clarify my understanding .

Also, if a person can continue to change employer once his first 140 is approved , and no additional 140 is required till he files for 485, then how this is different from EAD itself.

thanks
rahul