We use Advanced Shipping. When I ship and item using the Sales Order -> Item Fulfillment transaction, my inventory quantities are updated... when I create a Customer Invoice without Sales Order and without Item Fulfillment transaction, my inventory quantities are updated... BUT when I take a Sales Order, then create the Item Fulfillment, then create the Invoice the sistem allows me to add new item lines in the invoice... items that were not part of the SO->IT process, and in this case, my inventory quantities are NOT updated for this specific added items... ¿Do I have something wrong in my config?

I don't think so. It's normal to add items to an invoice, service charges, fees, etc. Maybe you need a script to prevent inventory or assembly items from being added to an invoice?

I already have a prototype... thanks @toltmanns