Automatic Voucher for Cash discount.

Dear Expert,

I have created payment voucher for customer and this payment take some cash discount.

After process completed and I checked in Customer Transaction found automatic cash discount voucher.

And then preview Voucher transaction as picture below.

Voucher transaction:

Now discount amount separate by 2 Dept.-Cost center but I would like to combine that 2 records of Cash discount
and specify for one Dept. and one Cost center(6039200-00-000-).  I'm not sure what parameter or something setup
was wrong.  Could anyone give some advice for me.

Thank you.

PrasitP.