What kind of weapon are you using?
For Production there is no benefit for a "Major" power factor weapon since everything is scored "Minor". For Limited 10, Limited and Open there is a difference between the two. Basically, the scoring zones are the same size, but they are scored differently. For example, an "A" zone for Minor and Major is five points, however a "B" and "C" zone is four points for Major and three for Minor, and the "D" zone is two points for Major and one point for Minor. Check out all the details at http://www.uspsa.org/rules/2010HandgunRulesProof3web.pdf
Good luck and have fun.