Fetch From Priority over Default Value

I want the Fetch From value (obtained from another field) to have more priority over the Default value always whether the Default value is empty or not (Fetch if Empty: off)
This is working fine.

However, If the Fetch From value (obtained from another field) returns an empty value, OR if the Fetch From field is empty (no link to another field) the Default value should be used
currently, the value will be empty, even if the Default value is there.