I believe that AMR don´t calculate expertise correct for Wrath Classic, or at least its a mismatch to in game since it rounds down to the nearest full expertise skill point.
Ingame shows 12 and 3.00%
It does not look like AMR does this.
37e1fe7199f24b91b4e97d14dda44ec1
Blizzard changed it many times over the years… I was unable to find any source that can confirm whether that rounding is for display only on the UI of the in-game character sheet, or actually in play for WotLK.
For now we assume that you actually get the benefit of every point of expertise rating regardless of what the notoriously inaccurate in-game character sheet shows.