Behaviors and perceptions of others normally take time to change. Also, we try to avoid over-surveying people so that when we do ask for feedback, raters would exert the maximum effort in giving it. You will always be able to invite new raters and choose new competencies and/or contexts within the 6 months. It is also a good idea to give yourself time to develop based on the feedback you receive, set action items that are challenging yet achievable, work on them, and when you do your next 360 degree feedback, you will be able to measure the progress on your own development.