Is it standard? NO. Does it frequently happen? Yes. I find that leaders who tell their Soldier to write their own evaluation report rarely understand the message the are sending to their Soldiers is “I don’t care or I don’t have time for you.” I would encourage you to make the best out of the situation and make a list of all of your achievements and do your best to make sure that the Boss see exactly what you have accomplished. It might also be wise to find a senior NCO you trust who has a lot of experience preparing evaluation reports and ask them to look over what you have prepared. You could push the point and tell the leader they are supposed to do the report but odds are you will be the one that suffers for it. The leader has given you the opportunity so I would prepare the best possible report possible!