It definitely is entertaining, and I hope everybody is keeping their humor about it.
Darkscout, Waltz, part of the problem -or misunderstanding, really- might be that Aerohance International Incorporated is much bigger in our imagination than in reality. All we know so far is that there is Susanne, who is suffering through this thread, and Bob. Maybe Bob doesn't like talking to people on the internet all that much. It's a fair guess that this thread is going to do nothing to change that. Besides, from what I've heard, Bob is an industrial designer, not an engineer.
What I've also learnt so far is that if you have a Golf it's a fairly safe bet that you are going to save some fuel with this device, unless you are puttering around mostly at 30mph. Is this the first thing you should invest in if you are looking for fuel mileage improvement? Certainly not. Upping your tire pressure and not driving like a maniac (aka looking ahead) are cheaper and will also buy you a few percent each. After that, your choices are to glue some paper maché bumps to your roof ( or worse: google kammback) , or, if you or somebody in your life cares about what your car looks like (or you ever plan on going on a second date), buy something like these gizmos.
If you don't drive a Golf, it's a bit tougher. You can try to sift through the reports on the Aerohance website, or go by gut feeling (similar rear shape is probably a good indicator). It would be in Aerohance's best interest to change that, but maybe there just is no engineer. Or maybe the stuff sells just fine. (Of course it always could sell better.) I still think they should try to find somebody (doesn't have to be an engineer, a niece or nephew or neighbor who hasn't flunked math is all they need) to sift through their incoming data.
Oh well. If it were me, maybe I'd decide that arguing with people on this website is just not a good investment of my time. Except for the entertainment factor.