Good catch, I've now fixed (dcl-Form-Resize) and (dcl-Form-CenterAndResize).
I've considered adding some function for returning the display scaling value, and I would have added one if it were as simple as adding one global function. Unfortunately it would need to be a member function of the form class, because display scaling can be different for each monitor, and display scaling of a form thus depends on which monitor it is displayed. For the same reason, there would need to be an event added for responding when display scale changes (e.g. when a form is dragged to a different display). It may ultimately have to be done, but I'd like to avoid adding more complexity as long as possible, at least until I fully understand the requirements.