How many surnames should you share?

Some Relative Finder users feel that they only need to share the surnames of their grandparents and that would be sufficient to confirm a Relative Finder match. Unfortunately this is not the case unless the matches are 1st cousins. Please use the chart below to determine how many surnames you may need to share in order to find a potential match.
 
Cousin Level  # of Potential Surname Matches
 1st Cousins  4
 2nd Cousins  8
 3rd Cousins  16
 4th Cousins  32
 5th Cousins  64
 6th Cousins  128
 7th Cousins  256
 8th Cousins  512