I definitely agree with you, would be much more money based on long-term losses. However, if I was a sportsbook, why would I offer long term losses. Who knows what the industry norm is...
I was thinking why else they would make that rule and then it hit me. They could make the rule to ensure that non-US players play at all of the affiliate books instead of just one.
This would also make sure books who advertised got a return on their money.