It can get the best part of 2000 Spdef with Amnesia, if that's what you mean. I still don't understand while you feel the need to use 3 Amnesias with Snorlax or, indeed, using it at all; 1 is plenty, 0 is enough. Wasting turns stat-upping usually leads to your downfall, because you're opening yourself up to a Critical Hit. That's why it's not a good idea to use 6 Calm Minds or 6 Curses, unless you're in a statup war..