Thanks Parveen,
I have linked the sales order item to the project header and the costs have also been assigned to the header. However, some costs still show up as unassigned. This does not happen for time recordings but only for supplier invoices. Not sure why. We have a lot of projects and we would struggle to manually assign costs or have the Accounts Payble person also manually key in the sales order item.
Do you know if there is any harm in leaving the items unassigned? For Cost to Cost Project POC, the system would still take the total of the project costs for POC calculations I think. So it may not be an issue under this method.
Also, I cannot find a 'cost estimate' selection under the Pricing and Invoicing tab of the Sales Order. Could this be a config issue? I can only see Item Pricing options but no cost related fields. Would you be able to send a screenshot? Thanks.