Inconsistent Campaign ID's

Hi Folks,

When I create a Campaign Campaign ID is automatically created for Ex.say Campaign ID is C-00000002.

Immediately when I create a Campaign under a Marketing plan or plan element from the hierarchy I get a campaign ID  which is not the next number C-00000003 but very different like C-0000200(which is not the next in series).

Can somebody tell me Is this a standard behaviour or what?

Pls suggest.

Regards

Jaya