Base plate pedestal height measurement

Merry Christmas first of all :)

This is about timber frame construction, and the floor structure itself is initially irrelevant. It is about the lower (wooden) threshold of the exterior wall that rests on the base slab and must be protected from moisture. Therefore, figure 14 of the target condition is correct (top of base slab = terrain +15cm). I also suspect a misunderstanding between the top edge of the finished floor and TOFF (top of base slab). In short, the house really needs to be 15cm higher.
As a result, this naturally means that you will have about 31cm of space between the terrain and the top edge of the finished floor, hence an entrance platform or similar will be required.

Our wish was also for everything to be level, so the robotic mower can drive into the living room, solid house. The reality placed the OKFB about 60cm above 0, and after filling paths and garden with necessary slopes, we have a step into the house, very reassuring during heavy rain. The step is at the entrance and from the terrace into the garden

Our wish was also everything even, basically the robotic mower can drive into the living room, solid house.

Should this setting promote a pairing of mowing and vacuuming robots? *LOL*

Actually not so dumb. Such a hybrid could also vacuum leaves in the garden and shred toys that are not tidied up in the house. As a disciplinary measure for the brood...

We have now spoken with our architect. He will raise the base slab by 15cm.

He said that since there are no height specifications in the development plan, no changes to the building application are necessary. It has already been submitted.

Is that correct? Or are we proceeding on a "hope for the best" basis?

We have now spoken with our architect on the phone. He will raise the foundation slab by 15cm.

Did he also say with what? - "raise" is actually only the correct term if it is already lying.

He said that since there are no height specifications in the development plan, no change to the building application would be necessary. [...] Is that so? Or are we proceeding on a "wing and a prayer"?

The latter. The development plan may not contain any limits (which I have not checked now!), but there are some in the architect’s plan. In the building application it is one document. I would definitely submit a revision there; otherwise, have him provide a liability waiver.