Sometimes latency is not the problem. Sometimes it is just bad timing when singing it happens to all of us. LOL
Lining up tracks to correct this can be achieved easily. These slightly out of sync portions can be corrected simply by either inserting a small amount of silence in the vocal track at appropriate places or deleting a small amount of track. You may NEED to use the undo button a lot and do it in very small steps but it works. Just drag the cursor highlighting the small piece of track you want to delete then go to edit and hit delete. To insert silence just place cursor where you want silence to commence and then hit generate and then silence insert the amount of time you want to add and hit it. Best to start in small increments. That redo and undo button comes in handy.

http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055