When you are talking about DNA shared, it is a bit random and the Family Finder uses an algorithm to make an educated guess as to what your relationship is. The best way to be sure is by making sure you have the correct info for your tree and adding your matches tree.
In your case, (Andrew and John were brothers. Anna and Julie Anne were sisters.) you and your match both share 2 sets of grandparents......Andrew and John's parents as well as Anna and Julie's parents. This is your MRC (Most Recent Common) ancestor that you share with your match.
Then you could use the easy way to figure out what degree cousins you are: http://www.wikitree.com/wiki/Special:Relationship
(Just keep in mind that this does not "Confirm with DNA" the MCA, to do that you need to triangulate your DNA with at least 2 others that come from seperate lines, so you and your cousin and 1 other.)