Why doesn't the 'sync music' amount and my actual list of songs match up?

I have my Iphone 4 synced to Itunes 11.3 but when I go to 'sync music' Itunes says I have 904 songs, but on my library screen the bar at the bottom says I have 957 songs. I have already checked and deleted my duplicates, (which has brought me to these numbers) and I have no 'track 01' songs or things like that, I keep my library rigorously organised. I have no idea where these extra 53 songs came from. Is there a way to compare the library on my Iphone to my Itunes library just to be safe (Ie with smart playlists)? Or is there a glitch to blame for this?