Thats not what I mean. You are not the copyright owner, you take it (under GPL terms) and upload it to the App store. The uploaded version is restricted, as per Apples terms. Users do not yet have the rights you need to grant them according to the GPL. You fulfill your obligations, granting these rights, in the next step.

Then, outside of the App store, you give everybody an additional copy. The GPL is satisfied, since the user gets to distribute the binary, and gets the source.

You are not distributing it separately under two licenses, but at the same time over two channels.

It's like you have a locked-down computer in a high security room, and I want to send you a program. "A" enforces the security of the room and while you can download stuff to the computer, you can't copy stuff from it. "G" supplies the software to me, and says I can give it to other people, as long as I allow them to have the source and pass it on under the same terms. I would say you can satisfy both at the same time by giving the customer an additional copy at the same instant, say on a USB drive.