The 5 piece bonus only works when the opponent is electrified (taking lightning damage over time).

The 7 piece bonus sacrifices the bonus damage you get from attacking the back of an enemy.

The page is missing Yagyu's Shinkage Style Set

Also missing Saika's Yatagarasu set

and warrior of the east set

and the crossed sickles set

and li the red demon set

and legendary mikawa warrior set

The set piece bonuses have levels, the levels depend on the equipped item level, therefor the bonuses change.