Just to be clear since my posting of 6R127 was likely confusing to some and some may have assumed it was a typo. So to be clear. Currently I am using, as we often do, Ford VINs to compare and organize findings since this is a Ford detail not a Shelby one. This allows me to include more data points (Mustangs built at San Jose in this example) which should make the findings more accurate and correct. Since they were built side by side, parts provided by the same vendors and installed by the same workers it's the best practice IMHO
So to be clear - currently the change over point I see indicated is around cars with Ford VINs starting with 127xxx. Since cars were not assembled/finished in sequential order the range is likely a few thousand one direction or another. Plus they (the workers supplying the bins or shelves) likely didn't wait until the bin was empty of all master cylinders before they refilled it. So you might have had a few stragglers. If the bin held individual cylinders then there may have been no stragglers.
Hope this helps explain better my earlier post - that I went back and added to.