I am pretty sure there would be some difference in the flights between fixed and mechanical but I'm not sure how much variance and probably depends on alot of variable including proper spine, etc. What I have noticed is that my fixed bh's don't really fly that much different than my mech's WHEN I HAVE CORRECT FORM. I have noticed that when I get a little sloppy, it seems there is less forgiveness with the fixed blades. I love the mechs but I think practicing with fixed is almost a training aid. JMO of course.