That's the thing, you guys are assuming harry casts first..
I don't think that's how a fight would go down.
They have to both start -non- buffed..
because if you say, harry can go invis, and sneak up on robo while robo is oiling his bearings..
Why couldn't robo sneak up on harry, with a 50 cal sniper rifile from like a mile away, while harry is brushing his teeth..