commissioned employee doinig hourly duties

[Groomer]

I am a pet groomer for a national pet supply store. I work on commission. My work schedule changed and I am now closing the shop two nights a week by myself. My manager has a list of duties that must be performed and initialed at the end of my shift. I find I am loosing commission since I must stop grooming at least two hours before my shift ends to complete these tasks which include mopping , wipping down the walls, cleaning out the drain traps, making remindere calls for the next days grooming appointments and much more. We have an hourly person performing thses duties the other five days of the week. The other groomers work their shift and leave. If they open the shop in the morning their opening duties are minimal compared to cleaning the shop at the end of the day. Should I dispute these "closing duties" and risk being written up and or fired?

It is certainly worth discussing and negotiating.

You should be paid for the duites if they are that time consuming.