Missing Order Id

[Unleashed]

At what point during checkout is the order id incremented? What would cause a gap in my order id? My order id skips over the occasional single order id and I am trying to figure out where they go. I assume some event happened that caused the id to be incremented without actually creating the real order but would like to understand when these ids are incremented and consumed and obviously would like to know what may have happened to my missing ids.

Thanks for any help.

[mazhar]

The order id is incremented when Checkout method is called on basket. StoreDataSource.GetNextOrderId(true)
is used to get next order id