Of course, every product is different, but the underlying principles used to calculate royalties should be the same.
All products are different in economic terms, including the various forms of artistic expression which comprise the goods or assets under copyright. That said, the underlying principles of competitive value and fair remuneration which, for an economist, mean competitive remuneration in competitive markets for the asset or product sold, should also apply to goods and services under copyright protection.
The practical application will vary, whether it is a composer, an artist, a producer, an author of printed textbooks or of a novel, and so on, but the underlying principles are the same.
I don't know if that answers your question.