I have the text version.. From the text it is not 100% clear whether the reference height is in the middle of the building length, or at the highest point, since there is also a longitudinal slope here. It is probably a matter of interpretation..?!
I would interpret that in my favor. Unfortunately, the surveyor did not measure the edge of the road. Just ask him about the height at the reference point in the west. Then I would place the house and garage 20 cm above the reference point with the floor. That way you still have a respectable knee wall.
How deep is the shaft in the north on the property? Is there also a sewage shaft in the S/E? Are there any restrictions regarding terrain modeling and retaining walls?