Field help (DACORD) 

Flag used to define the position of this element in the invoice element entry grid in the order header. It must contain a value between 0 and 10.
The null value means that the user does not want to manage this element in the order.
In the opposite case, this flag must contain the position (line number) where the element must appear in the invoicing elements grid of the order header.
When this element is displayed on the order, it is suggested, according to the context: