I think its fairly common for most call centres to only ask you to rate the person that helped you, as far as the automated voice prompts go they are fairly bad they never seem to understand what I say, although on the upside I hardly ever have to call in so thats lucky for me I guess.
I am not sure how MC's call centre works but I know of a few who have fantastic stats simply because of the way they measure themselves
Statistics can be viewed in so many ways. as a simple example:
99% of Calls are answered in 10 seconds (calls are answered by the system not a person in 10 seconds)
1% of calls are dropped before they can be answered (answered by the machine not the person)
90% customer satisfaction rating, (only because they ask if the person they got through to after waiting for 5 minutes or 2 hours was friendly, helpful, knowledgeable, etc)
So you phone in, hang on for 20 minutes the person answers after going through 10 prompts.. and is able to help you in 2 minutes, so you score them well, after all its not their fault you had to hold for 20 minutes, and before you know it, call centre X is listed as the best in the country.
Surveys are driven and steered by their questions. As long as the questions are crafted well a company will always have "good customer feedback"