Turnkey house - early acceptance possible?

The problem is that partial services would have to be agreed upon subsequently here, as this has apparently not been the case so far (including partial acceptances and separate payments, whereby installment payments do not constitute such). However, this must not be done solely for tax reasons. An indication here is also regularly the timing of the agreement of the partial services. This should regularly be before the effective date of the tax reduction, in this case therefore July 1, 2020.

The situation therefore unfortunately does not look good, as the entrepreneur would have to expect a repayment claim from the tax office. Therefore, I also see his interest in a contract amendment as low and he cannot be obliged to do so.

Regarding a subsequent change in the scope of services, one must be aware of the, in my opinion, serious disadvantages. Only the clear delimitation of the still outstanding work would have to take place and thus the work should be considered fulfilled according to the contract. Here I would therefore see rather opportunities.

An agreement must be made in advance about the partial services and their separate billing.

That is not the case here, is it?

It depends on what "in advance" means. In advance would, in fact, be if I make the agreement in November and the agreed partial service acceptance takes place in December.

You should best also get advice from a tax consultant, since we here are only laymen.

The problem is that partial services would have to be agreed upon retroactively here, since this apparently has not been the case until now (e.g. partial acceptances and separate payments, whereas advance payments do not constitute such).
However, this must not be done only for tax reasons.
One indication is regularly also the timing of the agreement of the partial services. This should regularly be before the entry into effect of the tax reduction, here therefore 01.07.2020.
So the situation unfortunately does not look good, since the entrepreneur would have to reckon with a reclaim by the tax office.

For every specific case, there is a clearly responsible tax office. It must and may not actively "advise," but it can provide information on concrete questions about which procedure it considers to apply. This information is also binding in the sense that—assuming no intervening legal changes—it must remain consistent with its statement. So formulate yourself or with your tax consultant an inquiry "to Radio Yerevan" to your responsible tax office.
In my opinion, "in advance" of the agreement does not mean that the arrangement merely precedes the payment processing in time, but the only suitable time would have been at the conclusion of the contract for work. An obviously initiated contractual amendment regarding payment due to the Corona special regulation—bearing in mind the difference between legal due dates and payment dates and bank processing times, as has already been pointed out—would, in my view, be at least an abuse of structuring. But, as said, the responsible tax office can clarify this with a binding statement, should it differ from my opinion ;-)
That an agreement preceded an actual jointly committed tax evasion is not synonymous with the "in advance" of an uncontroversial contractual agreement!
The essential crux here seems to me that you (in my opinion impermissibly) reinterpret the "time of agreement of the partial services" as the "time of agreement of the payment for retroactively virtually extracted service delivery sections from the overall contract, each considered individually completed."
This is— from my (non-legal) private perspective—a tax evasion by the VAT-liable entrepreneur (which, after review, will result in an additional claim for you, which he will also retroactively invoice to you within the billing period—however without the surcharges); and if you agree with him on such a "false" invoice, this could also be seen as a joint intent to evade taxes, which—in turn is my non-legal private opinion—would also violate the AO and the Criminal Code. So rather ask the responsible authority, not the community!

It was and is important to me to hear views like yours/yours and to take note of corresponding concerns that do not occur to me simply because I am an amateur. I will probably have it legally reviewed by a professional in due course.

Thank you for all the responses!

Honestly, I find your intention highly ridiculous. A house is an expensive pleasure. The 9000 euros (over the depreciation period of a house) really do not weigh that heavily. It’s not as if you are withholding the 9000 euros from a well-earning entrepreneur, but from society as a whole. And that is very unfortunate. Because especially in Corona times, more than ever, you can see how important a functioning society is with functioning "system-relevant" institutions. Whether the individual institution is paid exactly from VAT or from other sources is irrelevant. I definitely would not feel good about withdrawing from the social affair with such a, possibly even completely legal, trick for about 250 euros/year savings. Sorry for the moral sermon. I am very strict on this and find it creepy how some well-earning people fight over every cent, while definitely benefiting from the state and are not even ashamed to fight for so little.

Our situation is as follows: We had already - after detailed information from our side and clarification with the general contractor and their tax advisor - agreed to a partial acceptance at the end of the year when signing the contract. Unfortunately, the construction progress will not be as far as hoped (shell including covered roof, brickwork, stairs - probably without windows). The construction is accompanied/inspected for us by a client advisor from the Bauherren-Schutzbund, who would also participate in the partial acceptance. I consider it conceivable that the general contractor, if we want, would also waive the partial acceptance. The major risks associated with a partial acceptance are mentioned repeatedly. What exactly are they? (I do not mean the start of the warranty period for the accepted trades - I consider that a manageable risk.) The general contractor has a construction performance insurance. We have a fire shell insurance. It seems reasonable to me that we now also take out a construction performance insurance for the accepted parts. Nobody could really tell me if this is necessary, but it should precisely cover the arising risks. How do you assess the situation?

The situation unfortunately does not look good, as the contractor would have to expect a reclaim from the tax office. Therefore, I also see his interest in a contract amendment as low, and he cannot be obligated to do so.

Regarding a subsequent change in the scope of services, one must be aware of the, in my opinion, serious disadvantages.
Only a clear delimitation of the still outstanding work would have to be made, and thus the work should be considered as fulfilled according to the contract.
Here, I would see more opportunities.

I am now going to join the topic, because the clerk from our main contractor is contacting us every two days, saying that we could agree on a partial acceptance and that we should inform her whether we want to do that. For us, one could even define that relatively clearly, since by the end of the year the shell including roof should be standing. I do not expect that the clinker work will still be done this year. So a partial acceptance could represent the shell including roof.

In 2021, the clinker, windows, and generally all interior finishing would then continue.

I am a bit irritated by the insistence on the initiative of the main contractor. Due to the warranty risks, I actually did not want to try that at all. Now our buffer is currently melting at record speed, so of course we are beginning to consider whether this is not a point to replenish the buffer again.

Our risk: burden of proof reversal and confusion over warranty periods
His risk: additional payment to the tax office with reclaim over 3% based on the progress payments transferred until the end of 2020.

Silly question: You write above that the risk of the reclaim lies with the main contractor and not with us? I would have assumed that this is passed on 1:1 to us and recalculated?

The background is that a neighbor (another main contractor) started in 2019 and now wants to accept by December and assumed that the progress payments from 2019 and the first half of 2020 would be settled retrospectively at 16% in the final invoice in the second half of 2020. So, as the common forum opinion here is. However, his main contractor sees this differently. = July 2020 16% and not retrospectively all 16% at acceptance. The tax office confirmed this point of view to him?!

Anyway, I have no desire to get into the warranty trap for significantly less than €10k. If something goes wrong (which probably won’t happen), I would then have to prove that the defect already existed at the time of risk transfer/acceptance. In case of doubt, I simply believe that I would lose the game against the professionals.