It moves some about the column. The distance from the spindle to the column stays the same, as does the Tram (spindle bore being 90 degs to the table).
If you are not in the middle of a project, if it turns a 1/2" thats your new starting point. If you had a DRO, all you need to do is hit the zero. If you don't, you just find the center, or edge, or whatever, for your starting point, on the project.
If you have ever used a drill press, and moved the table, the relation of the spindle center to the center hole on the table changes, But the angle of the hole that gets drilled, to the table stays the same.
If you rotate the head, so it is not in line with the column, or 90 degs to the table, then you need to retram the head. That is the same as most mills. But also something you may never do.
Only times I can think of that I had somewhat of a problem, was: I drilled a hole, then wanted to use the boring head, but did not have enough room, so I had to raise the head. but then I lost the center of the hole, and had to use an indicator to get the spindle lined up with the hole again. Then use the boring bar. An extra minute maybe. Or when I needed to drop the head to continue boring the air compressor.
Yea, you generally hear them referred to as a mill- drill, But then compared to my Van Norman, it is mini. LOL.
Definitely prefer the PM, and the DRO.