Parviz,
You just remove the 10 against the discount condition type ZDCO ''from'' the field in your pricing procedure.Then create a fresh sales order.This should work for you.I have tested your scenario with successfully.
Please note when you are calculating the values from the above condition type you need not to mention any from field.
Also tick the exclusive indicator in your access sequence so that two prices will not be triggered.
Based on your screen shot below am sure you have forgotten to tick this exclusive indicator.
thanks,
Srinu.