I have very simple Drill Press (DP) actually, the basic one that you have to turn left-right to change the table height.
Sometimes, when I'm cutting wheels / knobs / circles with Hole Saw I get the 6mm (1/4") hole at the center but than, I want to drill larger hole for a T-nut or other reason.
The problem is that, I have to change the drill bit that is not always possible without moving the table down first (especially if the next drill bit is longer).
But, after changing the drill bit, I have to return the table to exactly the same point as it was before so the large hole will be drilled at the same center like the small one...
So, here is how I solved this problem...very Lo-Tech method but it works for me...