The damage isn't exactly the same. It's 4320 a stack in 10 and 6900 a stack in 25
http://www.wowhead.com/spell=123705.
We didn't find the fight a joke mostly due to the tank damage, definitely harder than the first 8 fights we did, Heroic Will probably harder though.
Yeah looking back the only fights that took more attempts than Lei Shi on H25 for us were Spirit Kings and Will and we're 10/16H. We're getting close on Amber-Shaper in a lot less tries. Different guilds struggle with different things I guess.