Rock band achievement problem

So I've gotten my tug of war achievements, but my score duel won't come. I have 23 wins, shouldn't I get the achievement? And this is where it gets wierd, I had 26 wins, I come back the next day, I have 19! It has done this about 4 times! WTF?Rock band achievement problem
well not to be a jherk or anything, but maybe u should just play the game and not care bout the achievements.