Same account showed in different journal entry lines when create invoice accounting

Hi,

I got a issue when create accounting in ap invoices.

In pic1 after create accounting ,CR showed in different lines while they have the same account.

In pic2 CR showed in only one lines if they have the same account.

The two invoices are same except for the amount and invoice number.

Anybody have any idea about this issue? When will the CR be created in different je lines even when the account is the same one?

Thanks!

pic1.

pic2.

Ying