I used the inputs from Spocalc and ran the UBI calculator. I got results that exactly matched those from Spocalc - 299.8, 299.7 and 298.8 mm of rthe front, left rear and right rear, respectively.

I suppose I should spend some time measuring my actual hub dimensions to make sure those inputs are correct, although they are a fairly well known commodity. I got the ERD from the VeloOrange web site. GIGO!

I was using these inputs:

FRONT
ERD = 606 mm
OSB = 0
WL = 34.0
WR = 34.0
dL = 67.0
dR = 67.0
S = 2.3
X = 4

REAR
ERD = 606 mm
OSB = 0
WL = 33.0
WR = 24.0
dL = 67.0
dR = 67.0
S = 2.3
X = 4