Becoming a level 60 in Mass Effect in just 2 playthroughs

Does increasing the diffulty actually increse the xp. gain when playing Mass Effect becuase i cant tell if it does. And if so, is it possible to reach level 60 in just 2 playthroughs on normal diffulty. I have unlocked all the achievmants that increase your xp. gain on my first profile. Like the Level 60 and level 50 achievements that increase your xp. gain by 20% and 10%. But since i want to create a new profile, I want to be able to achieve level 60 in just 2 playthroughs instead of 3. So with the Level 60 and 50 xp. inhancing achievements is it possible to achieve level 60 in just 2 playthroughs on normal diffulty.