MCO, yes one SWU upgrades you all the way, regardless of number of connections you may have, bearing in mind that connections are less than 24 hours between flights and there's upgrade space available. If there isn't at check-in you get in the DM list waiting for an upgrade but no need to hand any additional SWU on that itinerary

Savvy FTers use these perks to upgrade across continents, eg. Europe-USA-Asia/Australia.