Disclaimer -- Please don't take my advice but consult a good lawyer.
You have to understand , there are three things in the law, First is the written law, i.e. it is specisfied in black and white, what could happen and what could not, this by defination applies to very limited number of situation in life (one instance is trying ppl less than 18 years as adults, before US Supreme Court passed a law that no one less than 18 years of age can be tried as adult, it became a law that was very black and white, before that the law was there and many state intepreted it differently).
Second is the intent of law. This is where majority of law falls. More so in the immigration arena (as it is hard to make law concerning each and every situation, Congress has better things to do)
Third is by precedence. If something was decided one way depending on the situation, a similar situation would warrant the same decision. Here the loop hole is that no two situation are similar.
So we are back to square 1 with I-140 portability. The intent there was to support AC-21 provision that after 180 days, if a person has filed a 485 he can change companies. The obvious question was, what would happen if that person left and the company withdrew the LC. USCIS I guess came with the option that in that case it would be deamed that the I-140 (if approved) belonged to the applicant and his labor would be processed as such.
Now that's the law and I believe the intent. Now, one can push the envelope and say what if I-140 is filed and approved, it belongs to the applicant. That's true, but it was for people who had more than 180 days of 485 filed and had changed companies. Can someone take advantage of this situation and maybe selectively interpret the law to his advantage, I guess yes, that's what lawyers are for. Will you always succeed, I doubt it. Is the risk worth taking...well I won't I woyuld not loose my PD and strat from scratch, but then everyone situation is different.
Sorry for rumbling..
rgds
