bOS Values for 1byte are different in KNX

Hey,

Our client wanted to change ventilation speeds from the thermostat. Ventilation runs on Modbus everything else is on KNX bus.

This may be a really stupid question but... i found that when i put a value for 1byte in bOS 1 then KNX sees it as 3 and value 2 as 5. But in bOS it shows the correct values. Ventilation has 3 speeds that we control (0 is for away, 1 is home, 2 is guests) I made some screenshots. 
In bOS

Shows as correct value in bOS

But in KNX sees it as 3 and value 2 as 5 in knx

Is this normal or am i missing something? 

I got it working though by changing the values in the Thermostat to 3 and 5, there is no problem with value 0 :) . So now every thermostat shows the correct status and from every thermostat they can change the ventilation speeds. But I find it weird that it changes the values like that.

Best regards.