Yes. Broken is the way it works.
I've come across the same need recently and it is a truly awful thing. It looks like sheet scale, is shown like sheet scale, and is basically called sheet scale, but it is really scale for the model that was active at the time the sheet was created. So any models other than that one and every model added after that will have their own custom sheet scale.
The best I can suggest is that one can select a model by double clicking the model name at the bottom edge of the window instead of having to activate each model from RMB Activate and select. I don't recall if it worked, but if you Activate the model you want to drive the sheet scale and then reapply the format, it may set the sheet scale indicator to that model.
What's really nice about it is that usually a lot of models will require a lot of sheets so it's n^2 growth in the amount of work done to make sure all the sheet scales are coordinated.