Snap and Zoom

I've seen something to that effect. I noticed if the clip is zoomed out all the way and its a 4 bar or smaller clip  , Its very difficult to grab the clip with the smart tool because the area were select is in the clip is now shrunken smaller , So If I luckly grab the clip and try to move it based on snap setting it sometimes dosn't snap where it should thats the error I see..
 Now that said I find snap to work flawless besides that..So I Zoom in a little when arranging , also make sure you have magnetic strength set to off in your preferences , thats most likely whats happing to you as to why it's not snapping based on your snap setting. I also show the event inspector in my control bar, If you highlight the clip the event inspector will show you the start and end times of the clip so when you drop the clip you know if it landed on the correct time/bar. Also there Aim Assist .