Transmission rebuild

I am in the process of rebuilding a 1999 XJ8 transmission.

The ZF 5HP24 Repair Manual (98/08/01) page 3.5/6 specifies a Control Dimension: Cylinder AB to the transmission housing’s sealing area: approx. 20 mm.

My build is at 23mm. Is that too much and why might that be?

Any assistance would be appreciated.