15* should be fine as long as the front and the rear of the shaft are within 1* of each other. This being a CV shaft your binding may be comming from the "H" yoke inside the CV itself. If the pin, bearing are worn it will cause the CV to bind internaly.

Muddy, the marking of the yoke is just used as a precaution to insure that the shaft is "Phased" correctly. Meaning that the u joints all line up in a straight line , not even one spline off. This can cause vibration and premature wear ofthe joints.