The tasteing will be left up to the producer. So if you make light syrup at the beginning of the season and it has an off flavor from the snot in your tubing you need to label it as commercial. the hardest thing in my mind is when you make some grade A dark amber and it is a little strong so it should be graded B grade. light transmission is cut and dry either it is lighter than the test bottle or it is graded the next lower grade. But when it comes to taste then it becomes a determination based on your taste.
I guess the way i'm going to handle it is say to myself would I be happy if I were to have paid top dollar for the syrup I just bought. And remember that the customer will tell others if they are not happy. I have been making syrup for over 30 yrs and have also done taste testing of off flavors so I feel I'll be ok with the new grading standards.
Keith