No down payments in COSP, COSS table

Hello.

After using F-48 transaction to proceed down payments for WBS no actual cost are shown in COSP table. What can be the reason?

Already tried these things:

• Default cost element is defined in OKEP.
• In reports i alway tick the checkbox related to Vule type - 12 Down payments as costs. Still no costs
• After F-48 is executed no COSP table update is held.

We tried this function before with the same WBS and the same steps in creating down payments, so we are really confused why it is going that way. Any reply would be helpful.