They priced the A4 chip at $15, which sounds awfully aggressive to me. That's what you'd expect for a mass market chip for a item you buy in quantities of hundreds of thousands after all the kinks are worked out in the fab. This is a custom job, which hasn't sold anything yet. It will only get to that if the iPad sells huge numbers.

And obviously none of that includes the engineering costs to produce the chip in the first place.