via and netclass confusion

I might be missing something here which is why I'm asking.

If I change the via diameter and drill size in the Design Rules Editor, all the vias using that netclass (whether the default or another one) have their drill size changed to the new size but the diameter remains the same.

Is this the intended behaviour? I can't understand the logic here. To me, it feels like it should do one of the following...

1. Don't touch any already existing vias at all. The new settings apply only to new vias placed after the new settings are made.
2. Change the via drill sizes as currently, but also change via diameters and flag any that would cause a DRC violation.
3. Change drill and diameter sizes regardless of DRC violations and let the user deal with that issue.

At present it appears to do a bit of 1 and 2 so there isn't consistency between how it deals with holes and how it deals with diameters.

What am I missing?