Temporary VAT reduction by 3% until 31.12.2020

Not together or are these three different trades?

Yes, they are different. Everything was done in March/April/May and the interim payments were also made during that period.

But if the execution and the acceptance, by signature on the acceptance report, were already in May/June, it depends on the contractual relationship.

At that time (or earlier) there were no acceptances, neither from the site manager, the construction company, nor from me. There was only one acceptance date (last week), when we, together with the site manager, accepted the three trades and handed a note to all three executing companies saying something like "Yes, everything is okay, no defects."

My earlier question is still open, regarding what was agreed about the transfer of risk (reversal of the burden of proof). This plays a crucial role in the tax assessment here.

Oh sorry, I totally forgot that. Do you mean this? "The warranty of the executing companies for their respective services is 5 years from the date of acceptance of the respective trade according to the Building Code."

Addendum: From the company that said yesterday that billing must be done with 19% VAT, an email just came stating that the invoice will be corrected to 16%.

Then everything is fine

In the end, only this really confused me so much:

[...] we have signed the acceptance protocols for the individual trades of the individual companies.

And that was referring to the first half of the year

Now I am just curious whether I have to have the discussion with each individual company.