In the demo company from Microsoft (also known as Cronus) the Manufacturing Setup has been configured to use different number series for the different production order statuses. Configuring it this way make Dynamics NAV to assign a new production order number each time the status is changed (except when it is changed to finished). I have never understood why you would setup the system this way, and I have never meet a customer that wants the system to behave this way either. But, I have seen it being implement this way several times. It may makes sense to use a different number series for simulated production orders, but not for firm planned vs. released production orders in my mind.

The preferred way to set this up is to use the same number series for all of the statuses, this way a firm planned production order will have the same order number when it is released (which in my mind is a lot less confusing).

This is how is should look like if you ask me, all the statuses has the same number series;

Note: you have a similar case for invoices and credit memos in the sales and purchase modules, You can setup the same number series for both unposted and posted invoices (and credit memos) in the sales & receivables and purchase & payables setup tables. This way the posted invoice (or credit memo) will have the same number as the unposted one.