Ringtone in iPhone Ringtone folder, not on phone

I had 4 ringtones on my iPhone 3G. I made a few more ringtones tonight: used audio editing software on a song, selected a 15 sec clip, bounced each as AAC, put each on my Mac desktop, changed each extension to .m4r, and dragged each to both the iTunes Ringtone folder, AND the iPhone Ringtone folder. As I dragged them to the iPhone folder, the SYNC IN PROGRESS prompt came up on the phone, so I knew it was doing something. The first one went fine. Then, the second one ELIMINATED the first on the phone, even though the iPhone folder in iTunes shows both ringtones. I changed names, used a different song, and tried a number of suggestions on the web, but I cannot get any other of my homemade ringtones to "take" on the iPhone, even though they are in the iTunes>iPhone>Ringtone folder. I now have 8 ringtones in each folder (iTunes and iTunes>iPhone), but only 5 ringtones on the actual iPhone.

If the iPhone only holds 5 custom ringtones, why doesn't it eliminate the oldest one, and keep adding new ones? Plus, I read one poster who has 27 ringtones.

They are all .m4r, all less than :16 sec, all playable in iTunes, all in Ringtone folders, but I cannot get the iPhone to recognize them. I have 7GB of free space on my 16GB iPhone 3G.

Any help would be terrific.
rcarbaugh