To me, the way it reads initially is that Player B wanted to chain
Anti-Spell to
Wave-Motion Cannon being sent to the Graveyard and the discussion that ensues is whether the timing was correct.
Then it appears that another judge walks by and points out that
Wave-Motion Cannon doesn't use counters ... and thats where they loose us.
Obviously, the timing to negate the Cannon was wrong as it was already active on the field for at least one turn. But the questions that arise are when the Level 1 walks by and says this. I mean, sure
Wave-Motion Cannon doesn't use counters, but how would that have anything to do with
Anti-Spell's cost? PLayer B would have had to remove Spell Counters from HIS side of the field, not player A's side. So that's a confuses things a little.
In any case, asumming Player B had the Spell Counters to remove for
Anti-Spell's cost, he was much to late to negate a
Wave-Motion Cannon being sent to the Graveyard.