Which condition you are using for your RFQ ? Time dependent or time independent ?
For time Dependent :
You need to Check the gross price, is it PB00 or PBXX ? Check which calculation schema is assigned for the condition type in M/06. You need to add the condition type FRB1 to this calculation schema.
For Time independent :
You need to find the calculation schema which is using during the process and you need to add the condition type FRB1 to this calculation schema.