> the judge decided to come up with a HYPOTHETICAL loss
The judge issued a 96-page opinion [1] that details his crimes and the sentencing guidelines. It was not an off-the-cuff decision as you're suggesting.
> This seems beyond absurd and as far as I know has no precedence.
Your lack of knowledge on a subject does not make it absurd.
[1] https://martinshkrelilacksjudgment.files.wordpress.com/2018/...