Tiling: Surcharge for tiles differing from 30x60cm?

What justifies an additional charge for laying tiles in a size different from the standard 30x60cm, for example, if we want to lay a tile in wood look with the dimension 20x90cm?

Laying your special size is more time-consuming because it requires much more precise work. The substrate should also be prepared more thoroughly than with the small tiles. Otherwise, with 90cm long tiles, you will see every small height deviation.

Apart from that, you only have the choice to say yes or to take another tiler (who will, however, also charge an additional fee).

Our tiler even wants to charge an extra fee for 30x60. Isn't that outrageous?

We even want to install 20x120cm! How much is your surcharge? Whereas 30x60cm is now standard!

He writes the "normal" installation price up to 30x60 cm as €45.50 net. The surcharge up to 45x90 cm is €19 net.

I find that acceptable so far, but he charges endlessly on top for materials, site setup, 10 helper hours, disposal, site clearance. For making holes €8.50 net.

Other tilers say the installation price mentioned in the first sentence is okay - but then without additional costs.

You find that okay so far? Old Swede... if you say so? Is that your only offer?