Or they are aligning their prices against a psychologically meaningful breakpoint such as the increase from £7.99 to £9.99 given in the article, which happens to be about 25%, rather than a precisely 20% increase which would yield a price of £9.59.

People here are reading way more into that 5% than is remotely warranted and for ludicrously incidental reasons. What's actually happening here is very simple. Apple has been taking a hit for a while. They are re-aligning prices to the nearest logical breakpoint. That's it. All that analyst guff about Brexit downside risks because of a slight percentage discrepancy with exchange rates is just because analysts don't know crap about the real reason - marketing.