I have done that and I observed no change in the pH, or very little. It doesn't work. I don't know what your doing, but chalk is not dissolving into solution because it is not very soluble, therefore your mash pH is rising due to something else.
I do know it is very difficult to add alkalinity to water. Typically sodium bicarbonate is the easiest because it dissolves so readily. Pickling lime is less soluble, so the amount of alkalinity you can add is limited. Lowering pH is easy, raising it is much more difficult.
You can actually read up on it and learn the chemistry behind it or just assume your right and every one else is wrong.
https://www.braukaiser.com/wiki/index.php/Building_brewing_water_with_dissolved_chalk