Originally Posted by
swag
Not to mention, with a single flight number, miles are earned on the origin to destination mileage.
STL-DFW = 550
DFW-SJO = 1776
But STL-SJO = ~2016
So you get 310 fewer EQM/RDM with the same flight number.
Conversely, upgrading requires 4 versus 5 stickers. And, had STL-DFW been 551 miles, it would have required 6 stickers for the separated flights.
Cheers.