Same DNA Haplogroup for Two Family Lines

I recently received E3a Haplogroup results for Y-chromosome DNA tests for two of my family lines. Haplogroup E3a is also known as Haplogroup E1b1a. Both tests were 46-markers and were done through Ancestry.com DNA. The family lines with the matching Haplogroup are the PAIR family of Greensville County, VA and the THORNTON family of Halifax County, NC.

PAIR is the family of my father and paternal grandfather.

• Roy PAIR (1945- )
• Matthew “Mack” PAIR (1897-1987)
• Arthur “Ardie” PAIR (1864-1929)
• Hal PAIR (?-?)
  

THORNTON is the family of my maternal grandfather Minor Elwood Thornton (1913-1979).

• Minor THORNTON (1893-1966)
• Plummer THORNTON (1857-bef. 1910)
• Robert THORNTON (1815-?)
  

Although both test results matched the E3a (aka E1b1a) Haplogroup, only 24 out of 46 markers matched between these two family lines. (See matches in Red below)