I'm no where near a DNA expert. But it may be that they did something like an initial 12 marker test. With a 12 marker test you can get tons of matches. But if you upgrade it to a 37 marker you get closer and closer in your ability to make a positive identification of a relationship.---No interpretation, just more tests to narrow things down.
Well then I wonder ... how many markers did they test for? And is there a higher number than 37?