Staff of Sorcerer-Thane Thaurissan DPS bug

Re: Cataclysm Classic; the Dwarf Archeology item Staff of Sorcerer-Thane Thaurissan has a DPS of 231.2. It is supposed to be 623.33.

I found it with a my Death Knight character, Ouspenskya, playing in Azuresong, and transferred the staff to another Mage character, Ouspenskaya, (yes, almost the same name), playing in Windseeker, but the incorrect DPS showed up for both characters.

Edit: I should mention that I am referring to melee DPS.