Facepalm. It's because Quertuoso calculates the values based on PAL, and I'm using an NTSC machine.
@48kRAM Yeah. Thing is, I even read an old comment on the tool's page about not supporting NTSC.
But because the screen was fine, I assumed it was updated.
Thankfully RJ sent me some math to prove it.
@baldengineer I was just about to say that