I think this is just a case where you need to use your imagination a little. Many of the missions don't actually require you -- or allow you -- to fully complete the hack. As long as you show the requisite knowledge to get the information needed to proceed, you have completed the mission.
So in this case it seems you know what would have happened had your code change worked as expected, and this is in fact the reason for your q. But really if you think about it, the site is just saving you the hassle of having to go retrieve that information somewhere else, when it's already become clear that you understand what needs to be done in order to complete the mission.
Damn. My pony is slow.