I've seen it a million ways to Sunday on NOS vintage and new production. As long as the blade keep the same geometry from spine to edge and the shoulder does not protrude it's not an issue. I have old Mappins where the shoulder takes up 1/10 of the razor and is ground 1/4 hollow and comes straight to the edge. No issues honing. Same with some NOS Rudolf Grah's and others. You just have to evaluate when you hone it. If you get to the point you've reduced the blade width by 1/4" on a full hollow then you have honed up into the belly and should really look at a regrind or a new razor