What is the equation of basic exp?

My friend got 14054 points in one game. But finally, he only got 8658 basic exp, which gave him 38961 exp after all bonuses are calculated. So, what is the equation of basic exp? Why his exp dropped that much compare to his points?

This is another game. Also got really big dropping on exp.

I am feeling a big waste. I fought hard but only got half of what I should got.

Vehicles get around 60-70 % of the XP on the scoreboard.
Cant confirm this, but if you play against bot squads, you get only around 60% of the XP.
However: If you play engineer, you´ll find yourself often at the end of the match with more XP gained than written on the scoreboard.

According games I played in these few days, I think it is more about the time. The maximum basic exp is depending on how long you played. That’s probably why I only got 3381 basic exp here. 14 mins you can get about 4000, and 21 mins you can get about 5500.

Or it might be the percentage. Longer you play in this game, the greater percentage of points you get.

Time is a factor as well yes.

Xp per min I would say