The location of the round hole on the horn, so close to the ~4mm step up to the face, makes the hole pretty awkward to use. As a Pritchel hole, it is too close to the step to provide full-round support for punching. As a round hardy hole, maybe you could locate against the step to control rotation, but otherwise the step is a problem. Because of the step, the best use of the hole is probably just for a hold-down. If you need hole for a punch, use a bolster plate over the square hole instead--that won't mess up your work.If the makers wanted to make the round hole useful, they should move it more onto the face, extend the face around the hole, or raise the horn to match the face and provide all-round support to the hole.