I have been looking at the Box yDNA in the database on ySearch. It is true that 4 records show 0 genetic distance when 8 or 12 markers are used. Only two of the records, Linda's and mine used more than 12 markers. We each used 29. Using 29 markers, we have a genetic distance of 2, suggesting our common ancestor is around 1600 AD.
All four of the these family histories trace back toLaurens SC in the 1700s. This argues that at least two lines of Boxes were in Laurens at that time.