Comment by confusedcitizen

Well, this is the underlying logic indeed. What the author mentions is seeing 50 requests for 100 friends, where these friends might be divided into 3 servers. So, the keys are hashed to servers, i.e., if there is only 1 multi-get request, each server would see only 1 request. However, if there are 50 multi-get requests, each server would see 50 requests irrespective of the number of keys (friends) it caters to.