How does playing and none playing monthly loan fee actually work

[PandaIsland]

So I get the general idea but my few questions are.

The playing monthly fee is that paid EVERYTIME he plays? or just if he plays all games

What counts as unused if i have 4 games and use him in 3 what happens then? what if he is injured  and is it better to pay high playing and unplaying fees than doing wages

[Caning the Days]

My understanding is that if they play in any games that month then you pay the fee stated, or the same if they are just on the bench if that is detailed, but a definitive answer would be appreciated too