What's the point of the 4/8 person party buffs?

[Shiyo]

I kinda thought the idea for the buff's was that it was to buff small parties if you have 8 people then you don't really need these buffs do you?

Yeah I assumed it was going to make the 5 man parties give a bigger buff than the 8 man parties, but the 8 man parties buff is bigger? o_O; I don't get it at all. And how does this encourage you to group more? The game is already easy enough, now it's even easier? @_@; I'm really confused at this change.