Yes, that is weird.
Weirder is that my early 944 M/C has 23 cast in into the M/C housing for front and 19 cast in for the rear. This would 'suggest' a 'perfect' 23,00 mm and a exact 19,00 mm.
I haven't taken it apart to verify this tho (and its on the car now)
Maybe there are more different sizes made to suit different countries...who knows?
Best regards,
Walter