Garry Holloway considers the angles are more precisely measured than the percentages. Labs round off results and the effect on percentages is larger than on angles. The measuring tools also have differing abilities and software which result in more accurate angle readouts. That's why, I believe.
Karl K could also respond with some far more technical and highly knowledgeable answer, too.
JrJ - thanks for letting me know I'm not completely senile at 48, LOL.
Swirl68 - woah! Now that's some MATH! But damned if it didn't work!!!
Dave - ahhhh... gotcha.
And Karl, if you're reading this, no need for a more technical answer. After doing the math supplied by Swirl I'm not sure I can handle anything else today. (Kidding! Of course I always like to learn more.)