Modifiers in OM
I have the following scenario: I want to have a special item for additional charges on sales order, that will be entered on each sales order manually. Is it possible to achive such a funcionality via modifiers, that modifier would change the price on sales order for this item in this way - it would sum each item price from this Sales order and count 20% of this sum. Is it possible to achive this in the standard some how or there is need to create any customization?
Thanks for help in advance
Regards
Tomek