They basically denormalized all the dimensions.
Imagine you have a function which takes 5 arguments and returns one value. You could give me the source code and let me run this function. Or you could give me a mapping of every possible combination of the 5 inputs to the returned value. The former could be quite small, but the latter would be a massive number of rows.
If I understand correctly, in this case, that function's source is highly distributed in wetware. It's about as closed-source as it gets; nobody has anywhere near the full source. Each hospital is its own fiefdom!
But even if you had like 10M rows of pricing and then gave a 2% discount to entity A, 3% discount to entity B, 4% discount to C, etc.
You could publish these discount rules.
Or you could just multiply the 10M rows by the number of different entities giving 10*n M rows.
And then let the consumer of the data try to figure out the rules from the output...?