Promoting a level 20 multiplayer class adds 75 in single-player war assets to your TMR.
If I get to level 20 again (whether its with the same class or a different one), can I promote again to get an additional 75 points?
If so what is the limit to the amount of times I can promote each class?
There is no limit of how many times you can promote (whether its the same class over and over or different classes). You will gain 75 points of war assets each time and a boost to your N7 ranking.
The only draw back of doing so is you will (very slowly) lock yourself out of seeing any ending other than the best ending if you get some ridiculous amounts of war assets.
