Found another error:
WEAPONS-ARMOR!R16 - should read =IF(GEAR!B24="chain mail",16,0)
WEAPONS-ARMOR!R17 - should read =IF(GEAR!B24="splint",17,0)
WEAPONS-ARMOR!R18 - should read =IF(GEAR!B24="Plate",18,0)
Values should now be correct, however I think the armor tables need to be tweaked...