Hi, after the invoice has been paid it is too late for assigning the expense that you posted to a project. I could imagine using a dummy project to post the expense initially against if you don't know the final project at the time of invoice recording. Later on if the final project is known you could then shift costs via the adjustment functionality. Yet, to me this seems an odd behavior as things should get posted correctly from the beginning. Otherwise you can get a huge volume of transactions that you need to adjust. Maybe try to talk to the users to get them more aligned with the standard AX way of doing it.
All the best,
Ludwig
