As the fbx import / link doesn't allow you to define Incoming file units (the scale factor is automatic), it's important to maintain same Units Setup as the source application (in your case Revit). If you are exporting the fbx file from Revit in centimetrs, the System Units Setup in 3ds Max should be set to centimets also. The Display Unit Scale doesn't affect its size at all, just define units that 3ds Max will show you. Generally it's recommendable to have both of them using the same value to avoid any misinterpretation.
Then Brush Properties should correspond correctly to selected Dispaly Unit Scale. Attaching screenshot showing that Metric - Centimetres / US Standart - Decimal Inches conversion works fine.