The following are case studies from other DNA projects:
Beatty DNA Project
In the first round of test results, two of our samples were identical in 25 markers. One of them was named Beattie and living in England; the other was named Beaty and living in Indiana. Both had done a great deal of traditional genealogy and knew of ancestors in Ireland. The surprising DNA results prompted an intensive investigation of the Irish records and they quickly found the missing link about 6 or 7 generations back. They were both very pleased and further investigation of the Irish records continues.
This is just to illustrate that success is possible.