The league you're playing in has an effect as well. In Germany I got 1 red card in 6 years and always did well in the fair play league, same in Spain where my only red was in European competition. Using exactly the same tactic I got about 8 reds in my first season as Milan manager and didn't get any reds but did very poorly in the fair play table with Spurs.
It was more of an issue pre 8.0.2, but I have noticed that DM's get more yellow cards if they are played in a central midfield position on the pitch, whereas if you drop them back between central midfield and defence they fair better. That might just be my imagination, but seemed to work.
It's not your fault. The match engine even with 8.0.2 is a bit imbalanced in that central midfielders (especially defensive) tend to get yellow cards time and again whatever you do. It's a real pain when it's the lynch-pin of my tactics and I have to keep an extra pair of MCs in my first-team squad to cover suspensions.