Programming logic sometimes unknown, becauseTHEY (GS) do not write it in the owners manual, but, as example, plugged into shoreline, and generator cranked (on my 1999 motor home), the ATS (Transfer Switch) switches to gen, even if it is surging... not a lot of protection built into those control circuits ($$$)
JAYCO, OTOH, provides 200-page manuals vs GS at 37-pages... I LIKE my GS, but....