Auction Bug or what?

[Truewar]

I put an item for auction with buyout price 100,000.
My friend buyout this item for 100,000.

I open the letter... and get exactly 90,000.

I missed something up about comission or there is a bug?

[GrimNightfall]

10% auction tax.

[Truewar]

10% auction tax.

Pffffff...
I have to recalculate my trading policy then.