回复：Anyone has experience using valid H-1B visa stamp after chang

I do not think many people here have the experience because most of them are Chinese citizen. But I completely agree with your lawyer. The visa stam is just for entering U.S., and as long as you have a legal status in U.S. and prove it to the U.S. Customs official (it doesn't matter you work for Company A or B), you should have no problem to enter U.S..