What are Facebook Ad Group Keyword Stats?

Right at the end of the Ad group graph documentation, it mentions keyword stats. Having managed to find an example of where we're using this, I'm not entirely sure what the stats are I'm recieving.

For example, I get keywords stats (retrieved at ~2011-11-02T09:55:00+0000):

{
  "data": {
    "electronics": {
      "impressions": 2388, 
      "clicks": 1, 
      "unique_impressions": 557, 
      "unique_clicks": 1
    }, 
    "mobile": {
      "impressions": 3159, 
      "clicks": 2, 
      "unique_impressions": 637, 
      "unique_clicks": 2
    }, 
    "photography": {
      "impressions": 202929, 
      "clicks": 83, 
      "unique_impressions": 38692, 
      "unique_clicks": 83
    }
  }
}

That's a total of 85 clicks.

Getting the stats for the last 7 days, I get:

{
  "id": "6003855466377/stats/1320192000/1320796800", 
  "impressions": 203984, 
  "clicks": 82, 
  "spent": 4715, 
  "social_impressions": 0, 
  "social_clicks": 0, 
  "social_spent": 0, 
  "unique_impressions": 38753, 
  "social_unique_impressions": 0, 
  "unique_clicks": 82, 
  "social_unique_clicks": 0, 
  "actions": 0, 
  "connections": 0, 
  "adgroup_id": 6003855466377, 
  "start_time": "2011-11-02T00:00:00+0000", 
  "end_time": "2011-11-09T00:00:00+0000"
}

Which says 82 clicks. I've tried various interpretations of the "past 7 days (excluding the current day)", and I can't get the figures to match.

Why don't the stats match? (Is this a timezone thing?)
Can I get keywordstats by day? How?

This would be a really useful metric for our Facebook team here, especially as Facebook advertising is still a new(ish), and evolving, tool for us.

EDIT

Ok, so I can understand that keywordstats are duplicated (if I'm interested in mobile + photography, then an impression counts twice), but surely having one category that's has higher clicks than the entire adgroup is still wrong?

Solution

we have encountered this problem already with our application and this is what we were able to understand:

keywords stats represent how many clicks you get for a specific keyword from people you were targeting for one or more keywords. As you seems to understand now the direct sum of this numbers automatically exceed the total amount of click that you received.
those stats should be used as an indicator and not as a valid data, if you wish to have the time series you should query for it each day and do your math. This actually would help you to see if the target is too limited and is running out quickly (strong decrease of CTR after few days).
numbers vary a lot from day to day, you should be not surprised at all if the same query gives you a value today and a different one tomorrow. Despite clicks may remain the same, impression do not, we have seen changes a week after the campaign ended.
this data are not always available on the first day of the campaign, it can take up to three days to have them.