$221 is the total price I would pay through my Auto Club for the cost of the flexi-pass covering all the days and places I need to travel - London to Glasgow, Edinburgh to Leeds, Leeds to Cardiff and Cardiff to London.
When I checked on the nationalrail.co.uk site, the point to point prices for all these journeys totaled more than the fexi-pass would cost. However, I can't yet input my exact travel dates, because they are upcoming in October and the national raid site won't permit price checking for my dates just yet. So I am basing these point to point price estimates on using the same days of the week in September that I would be traveling in October. I'm assuming there won't be much difference between the last week of September and the first week of October.
By using the Rail Europe link here on Rick's site, the fare for London to Glasgow alone is $229. That sort of convinced me that the $221 I would pay through my Auto Club for the flexi-pass would be more cost-effective.