The standard value fixtures have knobs to dim the various channels- If there is already a manual dimmer installed, wouldn't it be possible to remove the knobs and dim via an apex and VDM instead? Or are these dimmer knobs not controlling the ballasts in the same way that the VDM does? if this is the case how are these knobs changing the intensity of LEDs? i was under the impression that LEDs don't work via normal resistive-dimming methods. Thanks for your help!