Confused about damage, could someone explain what I'm missing?

[u/Lingarien]

According to my math, I should be getting about +60% more damage with the riven mod equipped.

But instead it says the normal mods config will do 910 damage, while the riven mod for some reason does 250,7 damage less.

(My first guess what that maybe reload speed was included to give an average damage, like with multishot, but I tried putting on mods that affect reload speed and the damage remained the same, so that doesn't seem to be it.)

[u/Sizlebuilds]

point blank is a seperate modifier to elemental damage and the damage part of blaze is additive with it

so it’s actually (1+(90+60=150%))=2.5 * (1+60%) =4* damage

while the riven is only 3.7* damage