Just to make it a BIT easier to get the full set of Prestige Armor (what with tokens being useless in that particular grind). When you are rewarded with something that qualifies as "Raid Gear" in Prestige Mode, the drop you receive should have a 100% chance of being a piece of Prestige Mode armor you don't already have, but one that you DO have the Normal Mode variant of. The only times this WON'T happen are if you've either got the full set already, or all remaining pieces are ones you don't have the Normal Mode variants of. This way, for people that have grinded the Normal Mode and gotten the full set will have a much easier time getting the full set of Prestige Mode Gear.