If you already upgraded to XE4, but didn’t buy the mobile pack, it appears that EMBT penalizes you if you then want to upgrade to the mobile pack. According to this pricing page, the mobile pack AddOn is $499 if you already own XE4 or not. Seems to me it should be $449 to reflect the upgrade cost from XE3 to XE4 if you bought the special, or whatever you paid for your upgrade.
What is also baffling is that there appears to be no way to experiment with the iOS mobile pack. The trial says it contains “Trial includes Delphi, C++Builder and HTML5 Builder. Instant Trial includes Delphi and C++Builder.”. There is no mention of the mobile pack which for many would be the primary incentive for buying an upgrade over XE3, and the reason EMBT is reporting year over year growth.