I had the end off my 38 button Jefferies when I noticed something I had not seen before. Some of the holes on the inner side of the action board had wood removed to make the hole flare out to one side.   What’s that all about? Would this change the timbre or perhaps the volume of the tone? I think the practical effect would be to enlarge the chamber.     You can see from the photo that five holes have been crudely carved wide... all to varying degrees.   Can anyone help me solve this m