Hello Capital, welcome to the forums - and good question!
Since there's no standard software to analyse these resolution charts, its down to the individual to read and interpret them.
There's three main things to watch out for: first the point where the lines are still definitely seperate, second the point where moire begins to blur them, and third where the lines can no longer be seperated.
Of course a lot of this interpretation is down to the individual, which is why two different people or websites using the same charts may conclude different results. The important thing is that each person is consistent so at least their own results can be compared.
I take the result from the point just before moire creeps in, so it's at the point where the lines are still discernably seperate.
There's a whole science behind resolving power and analysis and for more information you may wish to visit the site of the company which supplies our charts, Applied Image
There was also an earlier thread about this here:
http://www.cameralabs.com/forum/viewtop ... =line+pair