TBH, with vocal phrases, sample accurate lock isn't really quite necessary. While something with sharp transients (like a conga loop or a breakbeat) will show off it's slight drift with some flamming over a 32 bar drift, a vocal part coming in a fraction late will merely feel relaxed... or slightly pushed if early.

You would be amazed at how much you can slide vocal parts forwards and backwards in time and get away with it!

Certainly a LOT more than percussive material...