RE:Infringement I hear you, sucks losing money.
The only way Exro (so called) ignored this claim was under their attorneys recomendation. So I'm sure their feeling is that it's defendable in court. Also if Exro's patents didn't hold up the companies they are in bed with would never have given them the time of day.
That being said I wish I could hear from one of Exro's engineers on the difference in the patents.