Solid Edge Item Numbers do not correspond with Sorting order

The customer creates a drawing of an assembly.  They then define a Parts List.  In the Properties they add a column for Document Number. 

They also define that they want to sort the Parts List by the Document Number:

However, in the resulting Parts List the Item numbers do not correspond with the Sorting order.

In order to make the Item Numbers correspond with the Sorting order, in the Options tab activate "Renumber items/balloons according to sort order".

Now the Item Numbers will correspond with the Sorting order of the Document Number: