GW bonus on stats bug?

What you were expecting to happen, and what actually happened?
When I look in the Sentinels tab I see that I’m giving a bonus to my higher ranked guildmates.
i.e. Magic, Level 5, +5 Magic for me, +0.5 for higher ranked Guildmates (which mens Eika in my team).
So I suppose I should receive a bonus from my low-level mates too.
There are 27 other members that are low level than me, for a total of 127 levels in Magic. I think this means I have to receive a +12.7 bonus.
12.7 and my 5 levels = +17 to Magic in GW.

Emperor Khorvash does a damage of [Magic+3]
In PVP I have a Magic of 28 with Khorvash --> 31 damages
In GW I expect him to have a Magic of 28+17=45… and deal 48 damages… which is not.

Is this a bug or maybe I’m misunderstanding something?