This kind of thing makes shopping on Amazon a real pain.
I have a similar quibble with the order process when buying direct from Amazon. I never know exactly how much the order is going to cost until I get to the final page. There’s shipping, Irish VAT and the STG to EUR conversion. I created a GreaseMonkey script to make life a bit easier, http://www.17od.com/2009/12/14/amazon-prices-for-ireland/.
Hope you don’t mind me plugging it here Donnacha.