The Companons are, generally *very good* lenses. Some time ago, there was a great movement among the so-called "insiders" to use an enlarging lens one size longer than standard (i.e. 80mm instead of 50mm for 35mm format) with the idea that they were somehow, mysteriously, "better". What is written here is true - it is best to use the lens designed for the specific format.
This was a *very* strong myth at one time - with *no* reasonable logic to support it.
I consider that to have the same status as the so-called "Callier" effect ... that one, in *my* book is a myth as well.