Partial Confirmations of an operation

Dear All,

I created an production order and I want to confirm partial quantity of an operation.

But when I chose partial confirmation, and I put the partial quantity, the system didn't suggest the new time for confirmation. I must to calculate the time, for this partial quantity, and put the value in SAP.

It's possible to automate this process?

Thank you very much for your answer!

Regards,

Marian