Gardener only mentions net prices

I don’t exactly see where the intent is to be read here

If you suspect that the craftsman once again, as so often before (you know each other), sells you the net price, although he is obligated to tell us as end consumers the gross price, then you have the option to either ask or "just wait and see how Mr. Landscape Gardener will react when confronted at the end with the fact that you are now unwilling because you assumed so..." 6000€ is certainly a high amount, but ultimately only 16% of the contract volume. The smart consumer could have suspiciously asked – he had the opportunity several times. And it’s about the principle, isn’t it ;)

I think deviations of 19 or now 16 % from other offers in that range can’t be recognized by a private person.

That’s not the point. It’s about net or gross. The craftsman should have calculated on site. He didn’t do that.

I'm curious how it will turn out. We had that right at the beginning and learned from it.

I have an offer for the largest items such as earthworks, graveling, paving work, etc. Changes and additions were then agreed upon with the garden landscaper via whatsapp with a final price. And of course, I asked whether it was gross or net. But I can't have every little thing confirmed in writing with a signature. At some point, I have to be able to rely on the word and the verbal agreements. Because even a verbal contract is legally binding. It worked great with other trades as well, or do you have them prepare an offer for every little change? Smaller companies don't have the time to write an offer for every change and get extremely annoyed when you come around with that. When the garden landscaper writes to me that the wooden deck with substructure and planks costs 4,000,- Euros, I factor 4,000,- into my calculation and not 4,640,- 2x drainage channels at 700,- each Change of paving stones additionally 3,500,- Paving area enlarged 2,000,- Trees 1,000,- Extension of the natural stone wall 2,500,- ... These are such "little things" that only arise during the work and have to be ordered relatively quickly. We discussed these via whatsapp because he simply doesn’t have time to write offers for such changes.

If you suspect that the craftsman is once again, as has often been the case before (you know each other), selling you the net price even though he is required to state the gross price to us as end consumers, then you have the option to either ask or "just wait and see how Mr. Landscape Gardener will react when confronted with the fact that you are now unwilling because you assumed, etc..." 6000€ is certainly a large amount, but ultimately only 16% of the contract volume. The smart consumer could have asked suspiciously – he had several opportunities. And after all, it's about the principle, isn't it ;)

That's not the point. It's about net or gross. The craftsman should have calculated on site. He didn't do that.

Regarding the first part: That is your interpretation now, Alessandro did not describe it that way. I read the following: There was an offer for services (where presumably a gross amount with indicated VAT was correctly stated). Then there were several purely verbal agreements in which prices were mentioned by Gala, which Alessandro accepted on the spot, assuming these were gross prices. Clearly, he could have asked at least once, but on the other hand, as an end consumer, he may assume gross prices.

Regarding the second part: It means this: whether it is 16% or 19% more or less on a price, a (probably still industry-unfamiliar end consumer) cannot tell.

here is an example:

Somewhere I have to be able to rely on the word and the verbal agreements. Because even a verbal contract is legally binding. With other trades, that has worked great or do you have a quote made for every little change?

I completely agree with you. I would also forgo a written document. But I would have asked whether it’s net or gross. Let me put it this way: I’ve always done it, learned it in earthworks, stopped at the landscaping gardener. And now you come along and assume a straight price is gross ;) was clearly much smarter there.