Difference between Condition Type

Please explain the difference between Ek01 ( Actual Cost) and EK02 Calculated Cost.

These are the condition type that will display the results of the unit costing for certain  type of sales document. 

EK01 :  
If you use this condition type, the result of unit costing is issued to the first position on the conditions screen for the item. The value can be used as a basis for price determination. 

EK02:  
If you use this condition type, the result of unit costing is simply a statistical value which you can compare with the price. 

Please note the following points  :

1) The condition type must have condition category 'Q' (costing). 

2) The condition type must agree with the condition type defined for unit costing in the pricing procedure. 

I have a customer who is being offered two discounts ie k007 and k005, now I want to exclude k007 for the next 2 
orders or so? I have set the exclusion indicator for the condition type,but still the condition is being accepted when I create a sales order.  Am I missing something, how do I do it?

I think u need to change the validity of the condition record for the condition type K007 defining it not valid for that particular 2 months.  And also the settings of the Requirements as it is correct that it overrules the exclusion.