Sintons, Fairbairns and Hendersons

Family Tree DNA recently "invited" assorted dna participants to add Family Finder to their DNA knowledge, at a considerable discount.
This tests chronicles your autosomal dna, ie that you inherit from all of your direct ancestors, as compared to the Y-DNA used for Surname dna projects which is only passed on from father to son, or the mtDNA similarly only from a mother to her children, but only passed on by the female line.
Should you be lucky enough for Family Finder to find a match with someone else in their database, you get to see which bits of your chromosome you match on.
As this test is really only most useful for the closer generations, up to 5-6 generations, ie back to 2-3*great grandparents, to find matches, it was a bit of a long shot to expect Peter and Michael to show up with the distant ancestry that we shared, but we decided to proceed anyway.
Peter and I have Peter SINTON and Jane WIGHT as common ancestors, my 3*great grandparents.
Michael and I share  Walter FAIRBAIRN & Agnes ROBINSON, also my 3* great grandparents, but Michael's 4*greats.

As you can see above, the blue portions are far more prominent.
They reflect my shared ancestry with Bill. We share William HENDERSON & Helen Sinton WIGHT, my great grandparents.
I guess we can conclude that the overlapping pink and blue lines are shared SINTON ancestry (unless of course there is an undocumented relationship between Jane WIGHT, Peter SINTON's wife, and Helen Sinton WIGHT's ancestry).