Hello Heinz - sorry I will not post off topic items in the future.

I must add information about this card used in Aarau.
There was only one canceler of this type and it was used on both incoming and outgoing items. In this case the card was posted, then cancelled at midnight 24 December [24.XII.00.—12]. The receiving date stamp in the lower left was stuck again 1am on Christmas Day [25.XII.00. I—]. All other Aarau uses where the canceler was used for both outgoing and incoming show the same time simultaneously struck by the same clerk.

Here are other razor cancels used in later years when the machines missed the stamps. Obviously the clerk was stationed by the machine to see when the machine missed stamps and then hand cancelled those missed. Automation was different in those days.