Transfer Price for intercompany AR transactions - what data will be taken as base shipment date or A

Hi All,

We have a scenario as mentioned below

 We have created a new intercompany price list and attached it to the ship-to site of the intercompany customer.But we already have orders booked in the system but not shipped.

We want to know if the AR intercompany invoicing program looks at the pricing date on the sales order line or looks at the date that the transaction was shipped  or looks at the system date to get the transfer price

Does anyone has any idea on this