Would it not theoretically be possible to do a SDC in NRT (I assume this is what you mean by NAR) to an itinerary that has a same-day connection, assuming you're flying AC NRT-YUL, spending <24h in YUL, and on a non-basic fare (=$100pp)? This is difficult with contract agents, but it may be doable through the app once check in has opened for the NRT flight, if there's space available on the YUL-MCO flight.