i had a bad experience, I upped the diff2money by a factor of 10 so my first mission earned me 20k instead of 2k and so on. easy to advance the single player plotline this way, BUT throughout the last game arc missions even though I had money to be at level 25, it stuck me a t level 17 because it was a continuous rush of arc missions and there was no space for random missions. Random missions or after story arc missions it seems are when you get level up indications mostly. So I ended up diong the last bit in an anubis with level 6 guns, to my chagrin.