Starting with ringtones without redoing everything

I've never bothered to pursue adding ringtones to my phone, but I recently decided to try. After downloading a bunch of tones from the zedge app, I have them all sitting in my library, but whenever I try to check sync tones in the tones tab for my iphone, I get a warning that all of my content will be removed from my phone if I check this. I manually manage all of my other media, but would prefer to just have all tones sync, but I don't want to lose anything and I definitely don't want to have to go through each media type and redo all of the current contents of my phone. Why does clicking the sync tones box lead to having all other media affected? What is the point of having separate check boxes for each media type if changing how one type is handled changes them all? Thanks, Chris