Maple tree farms are using very primitive equipment for evaporating the water from the maple sap and turning it into the maple syrup. The difference between grade A and B is the concentration of sugars/minerals in the syrup. It takes 15 min longer for the sap to stay in the evaporator to go from grade A to B so basically the farmer needs more sap to produce the same amount of syrup of grade B than of A.
Anyways, I am 100% sure that no single maple shack in Vermont/Canada has the necessary equipment to remove Sugar from the syrup on site so it needs to be processed somewhere else. Regarding organic/non-organic maple syrup - if it comes from the farm there just can't be any difference between them. I am not so sure about Walmart brands but when I lived in Vermont I can attest that syrup I bought in Walmart there was the same quality as if I bought it from the farms.
Anyways, during 10 day Master-Cleanse you will get only 6000 calories from maple syrup (if using 6oz of syrup daily) and 3500 less calories are equal to 1 pound weight loss.
Is it really necessary to starve yourself to death during the Master-Cleanse because of the hopes to lose 1.5 extra pounds and buy shady staff instead of the real maple syrup? Your call.