I received a message from Apple today, in response to an earlier post. I’ve reproduced it bellow:
Your assumptions on UK VAT are correct; the iTunes Store sales prices in the United Kingdom are VAT (Value Added Tax) inclusive, as are any other goods sold in the UK. This is required by law, not by Apple policy. You can refer to the government tax website www.hmrc.gov.uk for an understanding of VAT laws. Every customer in the UK expects that VAT is included in their price, so this is not unusual for them.
To the contrary, USA customers are used to seeing sales taxes added at the time of checkout, and not included in the sales price of an item. This is how the iTunes Store reflects taxes—the same way customers are accustomed to seeing it as they would in any other store in the USA.
This is address in the FAQs on iTunes Connect, as well as explained in detail to anyone who emails iTStax@apple.com.
iTunes Royalty Accounting