Overall Differences need correction

My concern here is basically how little difference there is between a 92 overall offense and a 71 overall defense. I'm not sure if this is a struggle for anybody else, and I know a lot if people are going to comment skill issue, but there should be absolutely no reason my offensive line of 87+ overall and tons of experience can't block a defensive line with the best and oldest player being 75 overall senior with 1 year starting experience. No matter the adjustments I make to break the run game open my O-Line just doesn't seem to keep up. I'll have a crazy running game against a fellow 90+ overall defense but the moment I play Charlotte or similar tiered opponents my O-Line takes the biggest dump you can imagine.