Well before we go saying things are wrong we need to consider the queries and what they are grabbing. I have never seen an issue with them being incorrect here.
Content visible to verified customers only.
Basically the amount sold and the number of ads sold is recieved from your stats table and this is going to be what is reported in the stats.
I would be interested in how you are determining the amount sold is wrong. If you collected money from an ad that was not processed or marked sold in the system?
As far as admin statistics and main page statistics views and product count the queries are the same so have you tried turning off the cache?
Admin => Global Options set cache to no and timeout to 0