Option to exclude 100% option in rubrics

I would like to suggest that the rubrics not require the inclusion of 100%  option in the grading scale. I would like to be able to offer traditional A, B, and C grades as 95%, 85%, and 75%. Requiring that there be a 100% option either means that I have to include 100% and 95% (both of which would be described as an A and excellent work, so it wouldn't be clear to the students why there were different grades) or I have to treat 100% as the A grade and then jump all the way down to 85% for a B. Currently what I'm doing is labeling the 100% grade as "perfect" and letting them know that this grade will not be used because no one is perfect. I can understand why more objective subject areas, like math, need the 100% option, but in the liberal arts we rarely have a paper or exam that does everything as well as it could possibly be done. I would like to have the option to include or not include the 100% grade. Thanks!