i think they are saying there is fragmentation, but they can effectively group the different fragments into this much smaller list of buckets by the 5 major versions and the 3 screen size ranges. that leads to 15 possibly combinations, ( although i doubt an android 2.2 phone will have a big screen size and so on... ) So until a new major category comes out they still have there 10-15 "groups" of devices to test...