As long as you're trying different clubs out on the same machine the fact that the results are skewed or not doesn't matter. Considering this is your first set of clubs you don't really have any game experience to base it off of. If you hit one club 20 yards further than you would in real life, you're going to hit every club 20 yards further than you would in real life. The method of measurement is the same throughout the testing, whether flawed or not.
The skewed machine comes into play when people are trying out a new set of clubs and they are basing their decision by comparing it to how they hit the clubs they already have.
Take whichever one feels the best and you hit the best according to their machine.