Your tado° automatically lowers the temperature depending on the characteristics of your building and how far you are from your home. tado° lowers the temperature only so much that it is able to raise the temperature again to your scheduled temperature by the time you get home, i.e. the further you are away, the lower the Away Temperature can be as tado° has more time to preheat your home.
If you work very close to your home tado° would not have very much time to preheat, so it may not lower the temperature as much as you may like whilst you are away. In this case you can disable the Preheat Before Arrival and set a Minimum Away Temperature that fits your needs. Simply go to the Away tab of the Smart Schedule, move the Preheat Before Arrival slider to OFF and choose the Minimum Away Temperature that you would like tado° to let your home cool down to, whilst nobody is home.