Do raid drops scale?Follow

My guild is starting to get a number of regular players in the 50's. We are thinking about doing some raiding (we've done very little so far). I thought I read somewhere that the drops from raid mobs depend on how difficult the fight is...or something like that. For example a 52 Epic x2 mob would drop better loot for two groups made up of level 50 players versus a single group comprised of all level 60's. I can't remember where I read this...but does anyone know if this is true?