The website says to only look at really high values ( more than 0.99 ) and everything below 0.90 is "low risk".

It's 94% certain the VPN endpoint IP my work VPN (only 25 people, university IP) is a VPN/proxy/bad.

That's correct, but not at all correlated with us being likely to commit fraud.

It's 79% certain the office LAN NAT gateway IP is a VPN/proxy/bad.

My work desktop's static IP gets 23%, so that's something.

My home IP gets 60%.

(Is this thing just connected to a random number generator?)

A lot of students have buyer remorse when they realize the money they just spent online could have been used more wisely. Unfortunately, when a network has a small percent of bad actors, the network as a whole is punished.

I'm guessing it's more so that there's a lot of traffic coming from that IP that it was flagged as a proxy.