The Default Font Scaling property applies only when using the character cell coordinate system. This property is set to Yes by default, which causes Oracle Forms to scale all size and position dimensions relative to the size of the default font on the current device.
When you use the same device at runtime as at design time, setting Default Font Scaling to Yes or No has no effect. However, when a form is deployed on a different runtime device, the Default Font Scaling property determines whether size and position dimensions are scaled relative to the default font of the runtime device, or to the size specified by the Character Cell Width/Height values specified in the Coordinate Info message box:
About using the character cell coordinate system
About using the real units coordinate system