I'm building something pretty much exactly the same as a reputation graph / summary on the SO user page.

I'm using this API call to retrieve the reputation history: /2.0/users/109102/reputation?site=stackoverflow

..and I see this JSON response:

{
  "items": [
    {
      "user_id": 109102,
      "post_id": 4772273,
      "post_type": "question",
      "vote_type": "up_votes",
      "reputation_change": 10,
      "on_date": 1334436306
    },
    {
      "user_id": 109102,
      "post_id": 1252848,
      "post_type": "answer",
      "vote_type": "up_votes",
      "reputation_change": 280,
      "on_date": 1334135022
    },

Why do I a reputation change of 280 in the second item. Should that correspond with the 10 rep change I see as the 2nd last green bar on the graph?