I've been under the assumption that any purchases made through iTunes would go under iTunes credit if I had iTunes credit available to use. It's been done for the past couple of years when I used iTunes credit for my iTunes Match subscription, and lately I've been billed for my iCloud 20GB subscription under my credit card. Now, I've gotta a couple of iTunes Gift Card deals.. that I'd like to use every now & then. But, I wonder will Apple Music be paid using my credit card or iTunes credit. I'll probably wait until the 30th to find out.