Depends on whether your level is mounted right on your bow. If it's correct and the bubble is off, then the bow isn't plumb and the shot will be wide.
Like I said, though....if you sighted your bow in ....in a particular position....and shot it in the same position each time......what difference would it make if that position wasn't level?
I say none. Actually.....if you sighted your bow in and it wasn't level.....then you shot it level....you're screwing the pooch.