Rounding field is not updating while creating invoice from draft document using DI API

Dear Experts,

I am creating actual invoice from draft invoice using DI API and the amount of rounding field is going into discount but rounding field is not updating.

Draft invoice is having value in rounding field on footer. This is so strange.

I am using SAP 9.0 patch level 11.

Is there anyone who can help me in this regard?

Thanks in advance.