QAD - Where to change Fixed Rate on a Sales Order
34.99.26 Shows Sales Order Fixed Rate
Also, I would like to inform you that when adding a new line in the same order is going to make the fixed rate Yes. Because the fixed price flag is set to "Yes" for customer FIAT153. Attaching the snapshot for your reference.

If you don't want the fixed price functionality or fixed rate flag should be enabled on the orders for the customer FIAT153. Make sure to disable the fixed price flag from Customer Data Maintenance.
Script for Progress Editor:
Please find the script for updating the data.
Script to update the data:
FOR EACh so_mstr WHERE so_nbr = "FIAT153" EXCLUSIVE-LOCK:
DISPLAY so_nbr so_domain so_fix_rate.
UPDATe so_fix_rate. /* Update to NO*/