It's not normally suggested. Some necks may never get unscrewed in their lives, but others may be on and off quite regularly (especially those vintage style necks with heel-end trussrod adjustment). Offsetting will put more tension on the wood around the screw area, so is more likely to get damaged and the wood threads stripped with several removals and fittings. Just making sure the neck is firmly seated in the pocket and then clamped before drilling is normally enough. Offsetting is good idea if you never plan to undo the joint, but I can see some issues if you are going to undo the joint several times.

Once the guitar is assembled and strung up, you can then back off all four neck screws slightly. You'll probably hear a slight crack as the neck moves and is pulled towards the end of the pocket further by string tension. Then you can re-tighten and re-tune. It may do nothing, but in some instances it can slightly improve the tone and sustain.