I believe the gist of their findings is that the EFOC arrow isn't blown off target as much as a standard arrow in a crosswind, but because most of the weight is forward, the rear or the arrow gets further out of alignment with the front, again in a stiff crosswind, such that the EFOC arrow isn't likely to enter the target as perpendicular as does a standard arrow. That is, it will have more of a horizontal slant to it as it impacts the target, potentially reducing penetration. Don't know if anyone has measured the amount of penetration that might be lost vis-a-vis a standard arrow. This is assuming all other things are equal, i.e., arrow weight and diameter, fletch shape and size, etc. Smaller shaft diameter and smaller fletch reduces wind drift for each type of arrow. I'm sure someone will correct this if it's wrong.