My Sister is a NCMG and owns her own grooming facility, she hired a young girl out of grooming school about 4 years ago. When the new groomer first started she was doing about 2 dogs a day. My Sister always said first you get good then you get faster. My Sister let the groomer work at her own pace, taught her proper breed trims, scissoring as the grooming school she attended did not teach any proper breed trims. She bought a copy of notes from the grooming table for this groomer and still will jump in and help her when ever she needs it especially with scissoring and specific breed trims. Another bonus is where all the groomers are working at their own pace they are not stressed out therefore the dogs coming in for grooming are not stressed out. My Sister worked in a shop that pumped the dogs out, the groomers were stressed the dogs were stressed it was just not a good environment.
It never bothered my Sister that this new groomer was slow at first, she completely understood. This new groomer is now booking more dogs a day and is faster, it took her about 1 year to perfect her skills and once she started feeling comfortable her speed naturally started improving as well. Even my Sister only does about 6-10 dogs a day (unless she has me there to bath/blow dry then we do up to 14) and she has been grooming for 25 years! LOL It's all in what you are comfortable with, what you choose to focus on and if you specialize in certain things you can charge more. If you pump out more dogs than what is enjoyable to make more money you may end up not enjoying your job as a groomer and you can get burned out quickly. My Sister avoided burn out and health issues as she enjoys what she does and works at her own pace and does styles which she enjoys.
So basically if your boss is not too worried about it you shouldn't be either. Unless it's money that you are concerned about. If you are an excellent groomer with talents then you can charge more for the end results, there are people who will pay more for perfect styles.
I also highly recommend attending grooming seminars. My Sister plans on taking her newest groomer to Hershey this year and has attended many seminars in the past and has competed. It's always refreshing learning new skills and sometimes their are seminars on how to speed up your work.
I hope this helps you a bit
I wouldn't be too worried about the amount of dogs you are doing a day right now.
Just to add, I bath and blow dry on Saturdays and I can get about 14 dogs done a day that is if the majority are small dogs. If there are a few Newf's and other large breeds with double coat with a few small/med dogs thrown in I can get about 11 dogs bathed and blown dry. This is in a 6 hour time frame. I don't do nails,ears etc, but I am expected to have all the dogs 100 % dry and brushed out...the blow drying really makes a huge impact on how the entire groom job will turn out. For example if I was blow drying a Newf and did it wrong and let the coat curl that would be unacceptable.