Authorize.net - When you do a renew credit card membership & specify a different amount (e.g. more) than the membership it ignores that value

line 255 CRM/Core/Payment/Authorize.net

$template->assign( 'amount', $this->_getParam('amount') );

should be

$template->assign( 'amount', $this->_getParam('total_amount') );

The question I have is whether there are any circumstances where 'amount' would be available & not 'total_amount' - do we need to handle that?