Is an architect really that expensive?

That will probably also be the reason why you have not yet made a decision.

Presumably, and also that the development will not be completed until summer/autumn 2016. If everything goes according to plan. So... if everything goes according to plan.

Then I don’t know why you are dealing with it? In the price range you are in, the above items certainly do not belong in the standard specifications.

In the price range I am in, at least 50 sockets, externally foiled windows, underfloor heating, all surveying costs, LAN/SAT wiring in almost every room, interior window sills made of marble (not that strange wood-based material), warm edge windows, brick walls on the ground floor as well as the upper floor, mushroom-head locks, triple hook locking on the front door, or a frost-proof outdoor tap are included. I have also read several other building specifications where some or many of these items were missing. Of course, that does not mean we will stay at 50 sockets, but the additional costs here are rather marginal. When I compare the building specifications with others, especially with nationwide prefabricated house companies in Germany, I would say there is already more included in the standard than with many other companies. Which, as said, does not prevent us from adding something here and there.

No. One has, for example, only a 20 cm base slab, the next a 180 cm insulation in the roof. Another installs the sanitary rough-in plumbing in the base slab as well as in the ceiling floors, the next one skips a 7-chamber system in the windows or forgoes filling the ceiling joints/painting the roof soffits. I can expand this list with many more points.

What is bad about a 20 cm base slab if it meets the requirements? The question is serious; I am not familiar with this!?

What ultimately counts is the following: what operating costs does a builder have due to the choice of his building partner? nothing more and nothing less; a supposedly higher quality choice of tiles/sanitary fittings is still the smallest extra cost involved

Operating costs, what do you mean?

I wouldn't put myself out on a limb like that if I were you, we were initially also at €1295/sqm with standard execution according to the construction performance description, BUT along the way some additional custom selection extras were added, now we are at €1650/sqm, good that we included enough buffer, or precisely because of the buffer some extras were added.

In the price range where I move, at least 50 sockets, outward-foiled windows, underfloor heating, all surveying costs, LAN/SAT cabling in almost every room, interior window sills made of marble (not that weird wood composite), windows with warm edge spacers, brick walls on the ground floor as well as the upper floor, mushroom head locks, triple hook locks on the front door, or a frost-proof outdoor faucet are included.

Honestly, that’s really nothing special or expensive! You can still add a lot – turn the front door into a proper aluminum door with 5- or 7-point locking, buy 30 more sockets, are there still windows sold without warm edge spacers (what kind of profile, how many chambers, which glass, U-values, sunlight transmission), different marble than offered, and so on.

We really built cheaply with a high standard, with pure construction costs of €1,325 per sqm of floor area (= €1,520 per sqm of living area) plus additional construction-related costs like architect, surveyor, structural engineering, etc.
The exterior facilities with driveway are not yet included.

The price quickly reaches the level often discussed here in the forum. You get what you pay for. If you pay little, you get "little". You can also live very well with the "little," you just have to be aware of it.

So for us, during the contract negotiation and detailed planning phase, it became 100 € - 200 € more expensive per sqm again - and we did not do much but stayed with the "solid standard".

Sorry if I don't reread everything exactly now, but the prices of about 1500€/m² living space refer to the ground floor and upper floor. What do you usually calculate for a basement room (dumb question).