Not sure where you're going with the comment, but here's the reasoning behind my iniital qestion and why I asked it.
I was kind of hoping Subaru published weight limits the same way way the hitch vendors do, based on structural capabilities, or in the case of Subaru, vehicle capabilities. I get that regulators will modify the total weight number for any number of good reasons unique to their countries, and they do. I don't understand why the allowable tongue weight needs to follow along at 10% of the regulated total. Maybe it's per regulation? The hitch vendors don't do that, they base their numbers on structural capability, and it's up to the person doing the towing to adjust their load so that tongue weight falls within a reasonable range (9-15%).
Anyway, I was interested in establishing a tongue weight limit for use when NOT towing. That's more of a structural limit, since trailer sway is a non-issue (no trailer). I backed into an upper limit of sorts by looking at what other countries are using. Since Australia allows 397 pounds of tongue weight, that established a preliminary upper bound for those of us carrying things in the US (bike racks, beer coolers, small children...) with a hitch rack, not a trailer. (The heavy-bike-on-a-rack discussion is what prompted this thread. That discussion is at
('19+) - 2019 - Hitch and bike rack to carry two... It's mostly done.)
I ended up using the Oz limit of 397, then halving it based on a recommendation from eTrailer for extended/cantilevered loads. Further reduction is a good idea because the load is a dead mass on the hitch, and puts more load into the hitch when going over bumps than the same load applied through a trailer (more physics

). If you use that methodology with the US limit of 150 pounds, you won't carry much of anything without exceeding a "limit".