Yves. I think you've made a mistake with the score calculations...
Round 1 = 20pts
Round 2 = 25pts ... (20+25=45)
QF = 45pts ........ (45+45=90)
SF = 60pts ........ (90+60=150)
Final = 100pts ... (150+100=250)
As you add each round in, the player gets the points for the round by adding the rounds up... So if a player wins in QF, if you picked them you get 20+25+45 = 90. So QF gets +45, not 90.
It shouldn't make a lot of difference to the placings, but it will bring everyone closer together. Cheers.