Quick question Currently, if I buy an app it's available for use on both my iPod and my wife's iPhone. With in-app purchasing, will purchases be reflected acro

Quick question Currently, if I buy an app it's available for use on both my iPod and my wife's iPhone. With in-app purchasing, will purchases be reflected across both devices? If I upgrade from demo to full on one device, do I need to pay again on the other device?