Submit complaint button on homework already been graded by ATs/Professor

I have recently noticed that there is no potential option to submit a complaint against a grading on a homework which has been graded by the AT or Professor of that specific subject. Graders that constantly copy and paste gradings cannot get punished as per usual when homeworks get graded by five different users. 

An AT/Professor cannot view the gradings of other users through normal grading when they are issued Ungraded works in admin thus allowing invalid gradings to 'slip through the net' without the potential of being punished. Yes, typically in this scenario, an owl will be sent to the Professor with suitable evidence so that they can issue a warning of some degree to the grader in question but this is not consistent to what is usually experienced in a normal scenario where the grader will lose house points.

What I propose is that we add a submit complaint button on homeworks that have already been graded by either an AT or a Professor of the subject - perhaps we do not feel that the AT or Professor gave us a personalised grading (albeit this is very very unlikely) or maybe we want to report the grading which has slipped past all rules. 

If this is not possible, allow AT's or Professors to view gradings in the admin section where ungraded works appear instead of hiding these gradings and forcing Professors to search through the archives for these gradings. Thank you for your time, and I hope this all made sense (it is a bit confusing I guess)!