Guild Wars 2

So according to:
http://wiki.guildwars2.com/wiki/Rune_of_Sanctuary
(and in game matches)
The minor rune #2 gives: +5% Boon Duration
The major rune #2 gives: +10% Boon Duration
But the superior rune #2 gives: +20% frozen duration
Is this intended? It doesn’t seem like it should be changing as it increases, and was hoping to equip it, but wanted the boon duration bonus.

i’m going to guess it’s bugged… especially if the first two gave boon duration…

That sucks, I want boon duration!