I have a number of matches on gedmatch; most seem to line up with the confidence level posted here. However you're right that it's not completely correlative. I have a few that appear stronger on gedmatch.

AngelaH, I think you'll eventually find that the 98% matches are related to you. It's just that your family line for those matches may not be far enough back. My strongest matches (outside of my siblings and aunt) are all in one family line where there was a recent paper trail breakthrough. The common ancestors are in the late 1600s, early 1700s. Once my family line was determined to be part of that line, then those trees made sense; they were 6th cousins or 6th 1X removed to me. The relationship was predicted as closer but I am sure that a few cousins marriages and the randomness of DNA inheritance enabled the relationship to appear closer.