according to my lawyer, it is best to get the H1B extension approved before
leaving the state. If your H1b extension is approved and you subsequently
use AP to come back, it will not affect your H1b status assuming you
continue working for the same employer . But if your H extension is not
approved and come back using the AP, you assumed to abandon your H and
choose to be as a parolee. In that situation, you probably have to file
something to resume the extension filing.