I could probably argue either side of this argument but the IAEI guys came down on the side that there was no specific requirement for a dedicated circuit for a disposal, dish washer or microwave. Without actually seeing the nameplate and installation manual, you can't really apply 210.21. It is certainly the right design choice but that alone will not limit you to a single receptacle.
Personally I think we have gone too far in the direction of overbuilding the electrical system in homes. I certainly don't want to go back to the bad old days of 60a services and 4 15a fuses but I also question 400a services in homes with $150 electric bills. When I was trying to decide what I needed in my new panel I turned on everything I would normally use with a house full of people (stove, A/C and water heater too) I had to turn on my 11kw spa heater to get over 100a, then it was 150 or so. I suppose my welder might have added another 25a or so but I couldn't see my Fluke with the mask on
