Again, there seem to be two realities. One, probably contractually agreed upon, does not provide for different screed heights in the rooms. Accordingly, one tile will be higher than other flooring, that's just how it is. In the other reality, namely that of , everything is supposed to be brought to the same level. Just the way the communication from the main contractor is formulated makes it clear what he expects from you. In my opinion, it is only a matter of time until the last main contractor and the last craftsman will avoid this construction like the plague.