If I spend £10 and listen to only Lily Allen I would expect her to get £7
If you spent £10 and listen to only Taylor Swift I’d expect her to also get £7
Howver I believe if I listen to Lily for 10 hours in the month and you listen to Taylor for 90 hours, then instead Taylor gets 90% of the £14 (£12.80) and Lily gets 10% (£1.40)