Why is a Karthus bot's requiem 100% accurate?

He only ults when he is assured a kill. Fog of war doesn't matter either. I had a new player in on of my games try out one of those sated jungler. He died to the camps a couple times (I expect this) and as soon as Karthus hit 6 he ults and kills my newbie jungler. Mind you, my jungler has yet to gank a lane and the bots at no point saw him at any point in the game.

I realize that there are more important aspects of the game that need attention but next time you guys are tinkering with the bots AI can you take a look at Karthus. He really shouldn't be able to hit his requiem with 100% accuracy yet miss 90% of his lay waste casts. Please give us some better consistency than what we currently have.