Number of views incorrect in Statistics

It appears that if you have an ad assigned to more than one group, the number of views reported in Statistics for an ad goes haywire. For instance, our site gets abou 240k views per month. We currently have 7 advertisers running banners. Each banner is assigned to 8 different ad groups, each ad is assigned to the same 8 groups. If I look at stats for each of those 7 advertisers it shows that each got about 192,000 views last month, which would be impossible.

Here is the telling part. If I look at stats for each of the 8 groups. Each of the groups shows EXACTLY the same number of views. In my case, each group shows 1352341 views for the last month. The same number for each group.

What seems to be happening is that each time a banner is viewed, the number of views is multiplied by the number of groups that banner reports to. Although, if that was the case, you would expect the views for each ad to be evenly divisible by 8, but it isn't. But dividing by 8 does give a number that seems to make sense, that is, it jives with numbers that we used to get prior to using Drupal and the ad module.

Ideas?