I put index marks on the lock nut and barrel in hopes I get the barrel back on exactly the same. Still check the zero. If you don't get the barrel back on with exactly the same headspace, I would expect the POI to change.

When going from one barrel to another I would expect to have a completely different POI. IMHO it would be dumb luck if they were the same. When you change the bullet seating depth 0.01 the POI will change.

Bill