Classifications?

Today I finished scaling my patient and I realized that patient classification often depends on the instructor you have. When I started my patient she was classified as a 1B but I thought her probe depths and tissues were more of a class 2. She just didn't have enough calculus to be a class 2. So the instructor put her as 1B. Then today the instructor I saw wanted to put her as a class 2 but couldn't because she didn't have the chance to see her initially... so she ended up being a class 5, which is probably about right. Either way, I took a whole hour to scale which means I am SLOW!!! My goal is to try and speed up just a bit. Maybe get my class 1B scale time down to 45 minutes.