Anyone know why the Duo (and supposedly other Doppelsetzers) have the same minimum front seat weight with or without a person in the back seat?

The rear seat moment arm has about 1/4th the effect compared to the front, so I would think a 200 pounder in the rear would reduce the front min weight by 50 pounds - nicht wahr?

Maybe the numbers are based on a super cautious approach for situations like an instructor jumping out when the student solos and forgetting to recompute the cg?