Comparing and Contrasting Planets

Today I had my class self assess and peer assess their statements about the compare and contrast maps they had made about 2 chosen planets. I had thought that after the children had self assessed it would be important for me to assess their statements as well to help teach them which level of SOLO Taxonomy they are working at but in hindsight I think I am wrong.
When I made my comments and shared them with the class I could see some hopeful faces looking very disappointed when I said they were not as high on the taxonomy as they had thought they were. It has made me wonder what the point is of me telling them what I think when they are capable of deciding for themselves and also assessing each others levels of thinking.
Anyway I have stopped leaving my comments and I am trying to puzzle through a better way to attack this. Maybe I should be leaving a comment with 2 stars and a wish to give the child some direction on how they could improve instead. Surely this would be more helpful for them and this is what I would do for any other piece of work that I was giving feedback on.