Depends on the gun. Some slugs will shoot similar to a pellet and some will go to the right but consistently. I shoot a lot of slugs so I am used to this. It is always to the right, I think because your rifle has a right twist. If your gun puts them to the right you have to adjust your scope accordingly. They should group into the same place? IF so, your gun would require a different scope zero for slug/pellet. I would zero for pellet and find how many clicks to adjust for slugs so you can easily go back and forth.
Really gun dependent, same bullet in one gun is same as a pellet and next gun to the right. I wish I knew why. Onc thing with slugs that does not apply to pellets as much, make sure your barrel is clean.
If you want to see why slugs are valuable shoot your pellet at 50 yards and then your slug aiming at the same point. The slug will be lower on the target because it is heavier. Then shoot both at 100 yards, again aiming at the same point. In all our testing, the heavier slug has caught up with the low BC pellet and is equal height to the pellet. If you go even further out, the heavier slug hits higher than the pellet.