Why does the number of achievement points I have change depending on what I'm looking at? Armory shows 9135 (I logged out, and it's still the same, been like that for ages), guild shows 8900 and my character pane itself shows 9245.
Most likely reason is that the Guild panel does not include achievements from other characters, only shows personal character achievements and not joint battlenet achievements. (for example alt characters with some personal's won't show on guild panel but will on character panel)
- Blizz did state they were supposed to update this, but I don't think they ever will.
Armoury is always behind on updates with achievements, so most likely your character panel is up to date and the armoury is just awaiting an update therefore will always be behind or equal.
I've been wondering this, too. My character pane says 10150 but my armory shows 9945. The armory counter refreshes my achievements automatically, though. I'll earn one, log out, and it'll be counted. Weird.