Laying tiles additional costs

Rectified just means that the edges have been reworked – otherwise they are tiles like any other. And they can be installed just the same. If you don’t insist on a 1-2mm grout joint, there is no difference in the installation.

Did you perhaps overlook this comment?
The additional cost, as you yourself already wrote above, comes from the possible narrower grout joints with rectified tiles. Of course, you do not have to choose those! So talk to your tiler about it.

So we were offered - Instead of 30x30 42x42 or 30x60 for 15-20€/sqm more - 60x60 for an additional approx. 15-20€ surcharge In that respect, it seems similar to what you experienced

So we were offered
-Instead of 30x30, 42x42 or 30x60 for 15-20€/sqm more
- 60x60 for an additional approx. 15-20€ surcharge

Insofar, it seems similar to me as with you

So 30×60 is supposedly included in the price
With the tiles, it is only about the rectified edges which is why they are more expensive.

The surcharge for the large-format tiles 20x120 is 34 euros

So it already seems more expensive to me than with you.

Did you perhaps overlook this comment? The additional cost is, as you yourself already wrote above, due to the possible narrower joints with rectified tiles. Of course, you do not have to choose them! So talk to your tiler about it.

We will.

So 30×60 is allegedly included in the price
with the tiles, it's only about the rectified edges which make them more expensive.

The argument that you charge extra because the tiles are rectified is complete nonsense. With rectified tiles, you can achieve smaller grout lines, that's it. You don't have to work more carefully or more precisely, which would of course justify a surcharge. Rectified tiles are more expensive because the production is more complex, but not the installation.

So don't let yourselves be taken for fools. Either he does it without the extra charge, or you find a new tiler.

Besides, do you really want to mix tiles (I understand sizes, formats, and color) on one floor just because you want to save money? Tiles are not laminate or vinyl that you can pull up if you don't like them after 4 years.

the tiles are only more expensive because of the rectified edges

No, there is no surcharge for that. The surcharge results from the installation with mini joints.