Can I just say finding out that Apple uses SAP on the backend is just one of those things that shakes my world view.
1) It's one of the largest SAP deployments in the US if not the world
2) SAP (at the time) was the only one who could offer an ERP that scaled to do what Apple wanted.
Homegrown enterprise software is one of those things that sounds great until you realize you're re-inventing a lot of code dealing with regulations (tax/hr legal) that is other companies bread & butter so it's worth "paying their price" rather than getting it wrong and being on the wrong side of litigation/legislation.
I understand that Cloud specifically is switching to manage accounting using SAP, but most of Google runs via our own in-house systems.
Source: work at Google in payments. This is only my personal opinion.
OH YEAH, APPLE IS PROBABLY USING SAP ON THE BACKEND!!!!!!
NO WAY DUDE THEY WOULD NEVER DO THAT!!!!!!!!!
Good times.
But originally the App Store was leveraging their existing payment infrastructure e.g. the one they use for iPhone sales. Purchases and invoices were done through SAP which was manually configured to support those price points. It's why you saw weird behaviour e.g. invoices for free app "purchases" and largely the limitations of that system drove what they could and could not do.
Perhaps they've done an overhaul for this system or migrated to a custom built one which is what has enabled all of this new functionality.