Oh yes, Bernard, lens coverage is definitively an issue and requesting for a different design.
Well, I am not doubting the fact that the Hassy 80 mm might not cover 6x6 at 2.8, but I am frankly not convinced that covering 6x6 with a 80 mm lens is a difficult task with modern optics.
I am aware of the differences between LF and MF lenses, and f22 is easy on lenses, but a Schneider 72 mm Super Angulon has a coverage of 226 mm @ f22. That's about exactly 3 times the size of 6x6.
Between 645 and 6x6, we are talking about a difference of about 1 cm diagonal. I assume that the mount of the Hy6 is a bit larger than that of the H system. More glass is needed, and that should translate into a higher cost, but the gap is just too huge to be justified by the technicalities IMHO.
But OK, I am not trying to convince you, just explaining you why I would never consider spending so much money on those lenses. I guess that 6x6 is overkill for me.