I know in the higher areans the plus minus trophy count is mostly team score and not dino lvls. I’m down 300+ trophies since the update (haven’t boosted yet).
Last two matches were -40 both times. If it’s based on your overall high score (5725), one opponent was 5637, the other 5928.
And if it’s of current score… well both had full boosted maxima (one swept me the other also brought out full boosted dilo and tryko as well). So I’d be pretty darn shocked if they were somehow even more trophies down then I was.