I would think this is the difference between "roll" and "result".
We play it as the actual roll has to be a double, and a LoC after modifying the dice is a casting roll result.
I will have to say, that is some weird logic there.
An objective does not count to see if a hex is empty, but you think an objective does count to see if a hex is occupied?
Occupied hex is clearly defined, yet empty hex is not.