I'm seeing 1-2 a game with my current settings. Try tackling at 54 and fumbles at 36 in all pro, that was my original setting and then work from there. Know that both tackling and fumble slider affect each other.
In all madden try tackling at 57 and fumbles at 38, you want tackling for all pro between 48-54 and for all madden between 52-59,for fumbles you want between 36-40