ASME Section-VIII Div-1 Appendix-1-4(d) Tori-spherical head calculation

[Champ58]

Appendix 1-4(d) has, L_o = outside spherical or crown radius [which is for OD calculation basis]
Many other components use outside diameter or radius value of new condition even if external corrosion is applied. While I found the COMPRESS app is using the corroded value of L_o in OD basis calculation. I think it should be of non-corroded value, am I missing something?

My F&D head dimensions were:
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Head OD = 48"
crown rad = 46"
knuckle rad = 4"
Min thk = 0.875"
SF length = 2"
Nom thk = 1"
internal corrosion = 0.0625"
external corrosion = 0.0625"

case-1, used in a COMPRESS calculation report
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L_o = crown rad + head min thk - external corrosion = 46 + 0.875 -0.0625 = 46.8125


case-2, I understood from the codebook
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L_o = crown rad + head min thk = 46 +0.875 = 46.875


Which case is correct?, am I missing something?

Thanks in advance.