Red can't give blue the full 20 points for his king because Blue doesn't have the material to force a checkmate.
Please use the notes/4 player chess club for this kind of discussion in the future
In case you have further questions, feel free to ask. Otherwise this forum will be deleted within the next 24 hours
why did the points split?
https://www.chess.com/variants/4-player-chess/game/84188493/168/2