What you are doing above in the variations UI is correct and should work fine for your device.
After saving your variations, check in the 'Variations' sub folder in the main CatTools install directory for the variations file which CatTools has generated for your device; you should see:
COMMAND_DISABLEPAGING = ""
COMMAND_ENABLEPAGING = ""
...which means the variation has been saved successfully.
However, what you are seeing when you reopen your variations file appears to be a bug in the variations UI (where an empty string value isn't populating the variations fields correctly).
I've added this bug to our tracking system, so thank-you for highlighting this to me.