I tried doing peer evaluations this way in the past and found that process to be dissatisfying for both me and the students. I have since gone to treating the peer evaluation as a multiplier of individual's team-earned marks and provide them with enough points to give everyone 100%. But if some team-mates have made greater contributions, they are able to allocate those points so some get more than 100 with the consequence that some team-mates will receive less than 100. This system seems to work much better for me.
Cheers
Neil