Hi Madhuri,
EK01 and EK02 condition types are useful when you have Actual cost and Plan cost
Basically these two condition types are useful when you have implemented Customer service or Project systems
I will explain a scenario taking one example from Customer Service
A manufacturing company sold an car ( for example) to customer using normal sales process with some warranty ( 1 year of free service). You will deliver the car to customer and invoice .
Customer has approached company for service after 1 year. You will do the service and capture the service activities using Service order created in IW31 transaction . In the service order you will enter certain activities of service such as
1 Oil change of Equipment --> 1 Hr
2. General servicing --> 2 Hr
3. Carborator cleaning -- 3 Hr
These are generally activities normally all companies perform to service a car. you will record the time consumed to service against each activity.
As part of Activity pricing done by Controlling team, cost of each activity for its respective hours is calculated as Actual cost into service order. Since it is out of warranty ( after 1 year) you have to create a Bill for the service performed, so you will create a Billing document which is termed as Debit memo request with reference to Service order. The actual cost incurred in the service order is posted to EK01 condition type in the Debit memo request
If you dont want to bill customer with actual cost, instead you want some fixed cost ( based on the customer group) then you will have option as Estimated cost irrespective of number of hours and services performed. This estimated cost is posted to Debit memo request as EK02 condition type
hope this is sufficient