i can't speak for the sliders affect but i use hoopcast for all games except tourney games and i give and take upsets. My most dominate player will have great games but not every single game. if there's a mismatch, that player will step up if my best player is shut down. whatever ratings your player have, whether good or bad, will come out during hoopcast. the biggest is a guy that has a high tendency rating for 3 pointers and can't shoot, he will screw you by taking bad 3's. you can fix that by toning that down by editing the player.
Just my opinion.