Kami,
Hope you have activated EA-FIN in your system. Even when activated, sometimes the flag doesn't get updated in the table TEB11. Please check the same in SAP Note 1561940. Since you see WIP Reval in CKMLCP, this may not be an issue.
I am assuming that you have made the necessary configurations in OBYC for transactions PRA, PRM, WPA, WPM. Also, if you are using activity revaluation in ML, then make sure to update activity update indicator in ML configuration and stop using CON2 for revaluation of orders.
Another important thing about activation of WIP Reval from help.sap.com:
"http://help.sap.com/saphelp_erp60_sp/helpdata/en/9e/9e7a74681f1d4f9ba6f5d64aba4a44/content.htm"
Here's the important message from the above link:
"You must activate the WIP revaluation before the start of the period in which you want to revaluate WIP. The activation will not be taken into consideration for the period closing activities for the current period, as the WIP revaluation is only activated at the start of the next period"
Cheers,
TD