All 3 are connected. If you have Humble at minimum and lower one of the other 2, the humble slider increases along with the one you didn't slide. Keeping humble at minimum while fine tuning the other 2 is really fiddly.

I set up a monthly donation to charity:water when IGN first added the sliders, before they lowered the humble minimum. It used to be 50%. So now a charity gets a bit more than I was donating through humble, and I spend roughly the same amount buying games elsewhere. I get a bit fewer games, but I play all the ones I buy. /shrug