What is the VAT rate for supplementary offers?

Hello everyone, we concluded a notarized contract for work with a general contractor/general builder for sum X in May 2020. In mid-June, we had the first meeting with the site manager, during which we were also handed a supplementary offer. We signed this on 10.7.20 and sent it by email to the general contractor. Another supplementary offer arrived by post on 2.7., which we also emailed on 10.7. Later, we were told that they would send us the first offer again and that we would have to sign it again. When we asked why, we were not really told, just something about the wrong paper, which we did not understand. On the original offer, sums had been handwrittenly added and crossed out. My suspicion was rather that this might not have been in order. We signed the first offer again on 3.9. Only today, our neighbors, who are building with the same general contractor, drew our attention to the fact that the general contractor announced a recalculation of the supplementary offers with the now valid VAT. The supplementary offers were always stated as fixed prices without VAT. Because of this hint, we looked at our first offer again and saw on the back of the sheet in the terms and conditions the changed VAT. We were not informed with any of the supplementary offers that the current VAT rate applies to them. I assumed anyway that since completion will be in 2021, we would have to pay the 19% (and that would thus also apply). Nevertheless, we feel cheated. How would you see it? Should the general contractor have adjusted the offer due to the changed VAT? Should he have pointed it out? How is it generally with supplementary offers, are they automatically added to the contract sum? Even if the contract for work has been notarized? We have looked at the notary contract and it states that price increases or decreases for special requests by the builder become due with the next construction progress payment. Can this be interpreted in a way that they can be fully charged, even if the service has not yet been performed? Our general contractor simply added the supplementary offers to the total sum so that the installment payments are now higher. Who has had the supplementary offers fully charged with the next installment payment? The matter is quite complex and I have many more questions, but I will stop here for now. If anything is still unclear, I am happy to explain in more detail. For now, I am grateful for any shared experience/knowledge.

notarial contract for work and services with a general contractor/generalübernehmer

What is that? Something is wrong there. A contract for work and services with a general contractor is not notarized.

First of all, you read what you are given and ask questions.

Otherwise, the fairy tale tax is a pass-through item for the general contractor. Otherwise, the general contractor calculated with the old rate in May, then the reduction came, he had to adjust his contracts. Apparently, that was not the case what happens in such situations.

Otherwise, I don’t understand the posting just because your neighbor is talking nonsense. Completion was in 2021, right? So VAT applies in 2021. You get nothing from it.

What is this? Something is not right. A contract for work with a general contractor is not notarized.

The land purchase contract was notarized on the same day and then it was said that the contract for work would also have to be notarized. My concern is not which VAT I have to pay, but 1) should the general contractor have pointed out that the additional offers would initially be subject to 16% and only later adjusted to 19% (as in the main contract)? I assumed that the final acceptance also applies as the service period for the additional offers, hence my second question 2) are additional offers automatically calculated into the total sum or are they considered as an independent “contract” because they are not notarized?

Should the general contractor have pointed out that the supplementary offers would first be adjusted with 16% and only later to 19% (as in the main contract)?

Why should he? That is not an agreement between you, but general terms and conditions. In the last 30 years, I have never had a conversation with a craftsman/construction company where it was pointed out that the VAT on the invoice might differ from the VAT on the offer. The current rate always applies at the time of invoicing.

2) Are supplementary offers automatically added to the total sum, or are they considered a separate "contract" because they are not notarized?

It depends on the specific contract design. In the commercial sector, I know it this way: the supplements "increase" the main contract and thus the individual installment payments.

However, he must in any case show the VAT at the applicable rate on a (partial) invoice to end customers. Otherwise, this would probably have been noticed earlier. I have also experienced that this is often not the case with my own contractor.