It's more simple than all that, I think. It seems to be just the way that the Google Web front-end caches results from the (presumably) expensive database queries.
Since I am currently obsessed with my AS numbers as a new recruit not yet in receipt of my first cheque (!) I poll my AS numbers freqently. To force fresh results from the database I change the query each time and avoid the cache, eg 1 Oct to day, 2 Oct to today, 3 Oct to today, etc. I mainly care about the final line for today in this case and I can get fresh results each time this way.