Ruby
I think you've misread the Guide
It is talking about the distances that ATOS and Capita
claim that you will have to travel, not how far you can be required to travel.
So ATOS claim that 90% of claimants will not have to travel more than 30 minutes to get to one of their assessment centres.
Capita claim that 91% will be within 90 minutes and 78% within 50 minutes.
I'm guessing that the 9-10% are all B&W members by the numbers of post with excessive travel times.
Gordon