Let's say you have a warehouse that loves to underfulil and you have an operations manager that doesn't want to map the warehouse fulfilled qty into the inventory detail of fulfilment record - what you get is an order that fails to fulfil and you can't see which line item is causing the issue. This is a massive pain for very large orders.

assuming you get the fulfillment json via some sort of api, update the order with the information from the json?

@battk yes, that's the solution I offered