I often come across "bad" answers (not an answer or LQ answer), that already have a canned comment.  

 - Sometimes it's pretty obvious that the comment was selected either while voting to recommend deletion in the LQP review queue or selected using the Auto-Comment add-in when someone else mod-flagged the answer.  

 - Other times, it isn't clear whether the answer has already been flagged/voted for deletion, or someone used the Auto-Comment just to advise the poster.  They may or may not be waiting to see if the poster improves the answer before flagging it.  

I'm wondering if my flagging answers that I expect have already been flagged/voted is a help or just extra work for the moderators.

 - If an answer was identified by the system bot as low quality, it already has a pathway to the 20K queue, where users other than moderators can deal with it.  Do subsequent moderator flags get treated as additional votes to send it to the 20K queue, or do they put the answer in the moderator queue (losing the benefit of the 20K queue)?

 - Does the system do any kind of useful aggregation with flags, so adding my flag provides some form of input to the moderators that multiple people have flagged the question (an indication that it might be a fast disposition)?

 - Does it serve no useful purpose, and possibly add unnecessarily to the moderator workload?