Numbers are created in the Diligence Room as Requests are Published (rather than created) so that both sides see (and can reference) the same Numbers.
When a Request is created, it does not yet have a number assigned to it. That is because numbers are only assigned to Requests when they are published. Similarly, if a Category does not yet have any Requests within it published, the Category will not yet have a number assigned to it.
The reason that dealWIP works this way is to make sure that both Sides see the same numbers for Categories and Requests. If Categories and Requests were assigned numbers as they were created yet still visible only to the Creating side internally, then the two Sides might ultimately see different numbers for the same Request (think about what would happen if one side had 10 Unpublished Requests, numbered 1-10, and then published only the 5th Request; would the other Side see the number "1" or "5" for that Request? If it saw "1", then the two Sides would see different numbers for the same Request. If it saw "5", it would be immensely confused).