Update: AdamJ and chriswatters were spot on.
Keeping the aperture and shutter values the same as before in Av mode, I turned the flashes to 1/128 power in manual mode, and like Adam and Chris suspected, the image was still overexposed at ISO 800. Now that my pea brain realized what was going on, I turned off one of the lights, and doubled the distance of the remaining light from the subject. This allowed the Odins to achieve the correct exposure to ISO 3200.
More boring tests:
Keeping the Odins in TTL mode and the camera in Av mode, but stopping the aperture down and/or decreasing the ISO, resulted in very accurate flash metering. In other words, shooting in real world conditions instead of some bogus set of test conditions that would never be encountered in the field, allows the Odins to function as they should. Man, I'm such an idiot
The really dumb thing is that I never shoot wide open, and in the rare instance that I'm at ISO 800 or higher - factors that contributed to this pseudo problem - it's because I'm in a dark environment that actually warrants it, not just for the sake of testing.
So I've concluded that the Odins work great, as long as the user isn't an idiot