Dear Zoho Book Team , 

After user create new Credit for specific invoices , it is a must to have status changed for invoices from Paid to : 

1/ Returned  : credit note approved but not yet refund

2/ Refunded : creadit note approved and Refunded to customer .

Currently it does not show any status changed for that invoices, it may lead to serious problems for finance or other accounting to do report or make use of those data for tax work.