We sell services; 

The price for this is agreed with the customer to 75%  per day  until end of year, and for 100% per day next year. The price lis of the service product is set up in this way. 

However, when creating the invoices after services have been performed, it uses the 75% price even for  invoices  created  after  1/1/2022 as (I think) it takes into account the sales order date, not the invoice date; how to make use of these pricelist when creating the invoice?

Any help much appreciated.