yeah it is.it really would be nice if the magnum torches just worked correctly with the F7 overlay. it's NEI that provides the overlay now right?
I suspect that to save calculation time NEI detects light levels rather than seeing if an actual mob can spawn. Integrating the magnum torch specifically may not be a huge challenge for chickenbones, but it would have to be special code for that specific block most likely, which I suspect is why it's not been done - there's no common system for preventing mob spawns besides light levels, and force-checking would be sloooow.