Client post-game Damage Bug

I'm pretty sure Yorrick didn't do more than 4 times as much damage as Ezreal and Velkoz (me) did in the game. Is this a bug or is yorrick just sleeper OP? Ezreal went 12/2/6, Velkoz went 4/0/10, and yorrick went 1/3/3. The picture linked is damage dealt to champions.