Datapoint Type 222.100 is a DPT with three sets of room temperature setpoints, each of which is a 16-bit float value. The room temperature setpoint comfort (TempSetpComf), room temperature setpoint standby (TempSetpStdby) and room temperature setpoint economy (TempSetpEco) are all encoded within the same DPT.
From the standpoint of the framework’s driver data model, each of these setpoints is a separate proxy point but, on the wire, KNX compounds them into one group address. Therefore, when it writes to the group address the KNXnet/IP driver must know the current value of every field before overwriting the DPT. To do this, the driver reads the whole group address before individually overwriting the data. This behaviour can be seen in the following ETS Group Monitor diagnostic of Group Address 7/1/0, which is a 222.100 DPT: