What is the VAT rate for supplementary offers?

Nevertheless, we feel cheated. How would you see it? Should the GU have adjusted the offer due to the changed VAT? Should he have pointed this out?

It's a pity that you feel cheated. I would not have that feeling. The offer did not have to be adjusted and a special note was not necessary either. For VAT, the time of (complete) service delivery applies, not the invoicing. Within a contract for work, partial services, if they are economically separable and accepted under contractually regulated conditions, can be invoiced at the VAT valid at the time of acceptance - maybe check separately if there are such partial services in the contract.

That is true, but that was not the misunderstanding the thread starters fell for. They thought he was quoting the additional offers with 19%. Because the general contractor simply didn't state anything, this was at least partially misleading. Mine does it that way too, except that he also tacitly accepted 19% from 1.07.-31.12.20. But I wonder about what amount we are talking about here. The difference is only about 2.5%. You would have to have placed a lot of additional orders in the six months for this to really cause such irritation.

I read the first post again carefully: At least for the first additional offer, which was still made in June, it should also have been issued with 19%. So if they then reissued it in July, left the amount the same, and today say there were only 16% included, I would agree with the OP that there is at least a mistake in the general contractor’s thinking here (I don’t want to assume bad intent yet).

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

Yes, it can be. In our case, this was indeed the case. The general contractor's subsidiary sold us the land, and the contract for work was notarized at the same time. Of course, that was clearly a tied transaction.

The GU should have issued an advance invoice by 31.12. including the additional services provided. Then, of course, with 16% VAT.

I reread the very first post carefully: At least with the first supplementary offer, which was still made in June, it should have been issued with 19%. So if they reissued it in July but kept the amount the same and today say that only 16% was included, I would agree with the OP that there is at least a mistake in the thinking of the general contractor here (I don’t want to assume ill intent just yet).

Exactly, he definitely did not behave correctly with this offer; we even asked again specifically and received no explanation regarding VAT. It’s about €760; our letter was in the mail today. In the end, it’s not the end of the world. I’m just surprised that the notary contract doesn’t say more about it. If the supplementary offers are added to the notarized work contract, don’t its terms and conditions also apply? Can two different sets of terms and conditions apply simultaneously?

Yes, thank you. I actually did not think about the tied selling or the obligation to the general contractor [GU].