I am nearing the end of my Invisalign treatment, tray 20 out of 21, and am worried that one of my incisors will not be fully in line by the end. I am due to go and be fitted for my retainers next month and refinements is something my dentist has never discussed with me. I am on the Invisalign full package but am worried I'm going to be charged more if I'm not happy with the results.