The XP Missions that require you to get 14000 xp require alot more than 14000, by my estimates twice as much.
Hunter Killer is one such objective that requires 14000 Combat exp.
However 3000 Combat xp in a game does not equal the roughly 20% it’s supposed to. Instead it is closer to 10%.
Were you playing Stopwatch?
I noticed that there only the second half counts for the missions. Otherwise you get your experience, you only notice with the missions. This would make it seem as if you needed much more XP.
I cant recall today but i generally play stopwatch unless its for an objective mission so most prob it was.