Remove locking cylinder at the steering lock

In the Guide "Electrical Installation" edition 12.91, the dimension of the bore required to press the locking spring is described. In this edition, a steering lock housing without rope hoist mounting, for the lock, is shown.
With the set bore of a=12,5mm and b=8mm the locking spring could not be pressed on the locking cylinder.(Bj.92 Automat with cable lock)
Is there any addition to the guide that describes an amendment or a proposal for this problem?
The position of the bore, marked in red in the appendix, is more suitable for me to operate the spring sheet.
Greetings and thanks