Mk5,I’ve heard elsewhere the reason you gave for extending Shabbos. It sound great until you give it some thought. Does it extend, as DY asked, from the first minute anywhere in the world to the last? Or does it apply just to those souls in your time zone?
You’re the one who brought it up. If it’s the first scenario, your extension of Shabbos only helps if you live in the last time zone that experiences Shabbos.