The main reason that SDQ uses wide-bodies on a regular basis is that all the luggage that doesn't fit on POP and STI flights can be put on this aircraft, and the pax from those 2 destinations can get their luggage on the same day. Also, before Jetblue started flying to SDQ (they are soon pulling out however), there was the increase competition. Maybe the 764 will come back to this route soon. The prices can be as high as $700 r/t over the holidays.