It wasn't a mistake if you read my explanation it was exactly what I intended.

If the user only looks at 1 page in that visit, you want the cookie to expire immediately, so that when they return to the site again later that day or tomorrow, they don't see the ad on their first pageview.

I guess that may not be what Sled wanted, as you say he'd show more ads. That's they way I would code it to maintain the fact that users only see the ad on their 2nd pageview of each visit, but only see the ad once every 24 hours at most.

Mubs