Thanks for the comments
The KMG Inversion - well, I've ridden this one and Dominator in Holland (both at their debut fairs, oddly enough). Both had the cars locked into place most of the time, and the ride was fairly average. Occasionally, Flash released the cars, and the ride became unbelivably intense - even by German fair standards. I think KMG may have messed up their calculations, and may have to work out how to run these rides in future!
And no, I've not heard of any pay-one-price fairs in Germany, mainly because a fair tens to be made up of rides from many different showmen. We have a few pay-one-price fairs in the UK, but I really hate them, as they tend to have no atmosphere, as the showmen have less incentive to hype things up.