What will trigger invoice reapproval at the header level?

Before applying the Oracle Recommended Patch Collection 4 (RPC4) we were able to discard lines (no header amount change) and reapproval was not required. Since application, these invoices now require re-approval. There is also conflicting documentation: Doc ID 2014023.1 says discard lines requires approval, Note 1437163.1 says only amount change requires, Bug 14561860- enhancement request. We only have header level approvals.