I don't think the arrival schedule changes much from day to day even at Christmas. The difference is how big and how full the aircraft are.
No matter what you still have to think that there are 15 or so flights coming into MBJ and their arrival depends on when they leave the US (weather, mechanical, etc) . MBJ is a turn around destination. Every aircraft that lands takes off shortly thereafter full going back to the US or Europe.
There jest ain't no tellin' how long it will take...
Don't worry...be happy