millradius tolerance, is this correct?

[set-soft]

Recently a user of KiBot pointed out an interesting question: a tab with 1 mm separation should get a correct mill simulation using 1 mm? In order to get consistent results you must use a slightly smaller tool, i.e. 0.9 mm

INTI-CMNB/KiBot#369 (comment)

The PCB is available in the issue. The KiKit configuration is:

{
    "cuts": {
        "drill": "0.5mm",
        "offset": "0.2mm",
        "prolong": "0.5mm",
        "spacing": "1mm",
        "type": "mousebites"
    }
    "layout": {
        "cols": 2,
        "hboneskip": 1,
        "rows": 2,
        "space": "2mm",
        "vbackbone": "4mm",
        "vbonecut": true,
        "vboneskip": 1
    }
    "tabs": {
        "hcount": 2,
        "type": "fixed",
        "vcount": 0,
        "width": "3mm"
    }
    "post": {
        "millradius": "1mm"
    }
    "framing": {
        "cuts": "both",
        "fillet": "1mm",
        "mintotalheight": "300mm",
        "mintotalwidth": "200mm",
        "space": "3mm",
        "type": "frame",
        "width": "5mm"
    }
    "copperfill": {
        "clearance": "2mm",
        "spacing": "0.5mm",
        "type": "hatched",
        "width": "0.5mm"
    }
    "tooling": {
        "hoffset": "2.5mm",
        "size": "1.5mm",
        "type": "4hole",
        "voffset": "2.5mm"
    }
    "fiducials": {
        "coppersize": "2mm",
        "hoffset": "2.5mm",
        "opening": "1mm",
        "type": "4fid",
        "voffset": "2.5mm"
    }
    "text": {
        "anchor": "mt",
        "hjustify": "center",
        "text": "{boardTitle}({boardRevision}), {date}",
        "type": "simple",
        "vjustify": "center",
        "voffset": "2.5mm"
    }
}