Weight question

My site is approved for co-op and my weight was 18,000 at the beginning. But it's still 18,000. Is it normal?

There is a small drop-down box under 'update' button including numbers from 1 to 15. What is it for?

Any help appreciated.

 

You weight won't change unless you get more or less pages indexed by Google.
The numbers are the % of weight you send to you add. 1 is the minimum, 15 is the maximum

 

I only have one ad to display. Which number should I choose?

 

If you only have one ad any number you choose will give you 100% weight.

 

Thanks mate.