Fast but no Exceptions build size (iOS)

This documentation http://docs.unity3d.com/Manual/iphone-playerSizeOptimization.html has a checklist that helps reduces the size of the build specifically for ios. One of the points says that you can use Fast but no Exceptions options instead of the safe one. But when I build - the resulting .ipa size stays the same. Is it supposed to reduce build size really? Or we just don't use some features so there is nothing to reduce? (But as I understood it uses different implementation if "Fast" is selected, so it should affect it). Or maybe size difference only can be spotted after uploading the build to AppStore? (after the binary encryption that AppStore does, but i doubt it)