Thanks for the message. Unfortunately, the options panel for paint is a built-in max interface that we cannot control. The same UI is seen in Vertex Paint, Edit Poly's Paint Deformation, the ribbon's free form tools and a few other places. I've double-checked and they also suffer from this issue when using scaling over 100%, it seems even in 2020.
I'm afraid, there isn't much more we can do from our side as that interface is completely handled by max itself. Thanks for your understanding.
All the best,