AR Credit Memo from Copy To Invoice

Hi,

I have a below scenario and need a details of SAP B1 behavior

Scenario:

In AR Invoice I have two rows of Items and first item with Price and second Item without price (giving free)

When I am coping to AR Credit memo from Invoice, SAP is populating only first row item (which is having price) to AR Credit Memo and the second row (which is not having price) is not coping in AR Credit memo.

When I raise AR Credit memo through copy from function all two rows are coping.

Why SAP is behaving differently on Copy To and Copy From Options?

Kindly provide a details if you have faced above scenario

Regards,

Kiran