Hi Ibrahim
You dont need a user exit for that..
1. Create a Valuation Strategy in KE4U - Say, 001
2. Assign 001 to PV = 01, Record Type F
3. Create 2 Costing Keys in KE40
a. Z1 - Current Cost Estimate
b. Z2 - Released Cost matching Goods issue date
4. Assign the Costing Keys Z1 and Z2 to Mat Types in KE4J or in KEPC (Z1 in 1st Column and Z2 in 2nd Column)
5. In KE4R, assign Value Fields in the 1st and 2nd Column
You can now do valuation based on both
Regards
Ajay M