The problem with the tado system is actually that it is made for 'simple' and 'standard' set up. Once you move (one step) away from this 'standard' the tado system gets a different configuration.
My example: a boiler and two valves that independently heat the ground floor and the first floor. Using a tado system then the Wireless Receiver becomes the Heating Controller and you call that also the Zone Controller. The Wires Smart Thermostate has the function of a controller (of the valves for the zones) and tells the Wireless Receiver that the boiler needs to start. The sensing of the ambient temperature from the Smart Thermostate is not needed in the event a Smart Temperature Sensors (Smart Radiotor Controllers) are used and will make the Smart Thermostate less smart.
Anyway, it works in the end, but some improvement of the documentation and terminology beyond the 'normal' situations would be helpful for 'normal' customers that want to something beyond the 'standard'. The sales support was excellent and made it work for me via the cloud ......... only, I don't know how they did it :-)