High power EOS (older generation of pinballs) can be problematic for sure. This is especially true if a previous owner just bought a generic "Williams/Bally flipper rebuild kit" and didn't pay attention to the hardware generation. WPC EOS will NOT work on a sys 11 - or at l;east it won't work for long. New EOS switches can't handle the high power of older flipper systems like sys 11.
Way better how they work now. Wish we could retrofit sometimes!