How to calculate condition base value in packing charge condition type in SAP?

Dear All,

Here, I am confused about condition base value for packing charge condition type, how it is calculating is a big question, attaching herewith all required screenshots for your kind reference. Please give your input in this matter.

First, we refer sales order

Item No. 20

Item No. 10

Header condition - packing charges.

Thanks & Regards,

Manu Prajapati