While I realise that people have different levels of comfortableness in the office, the air conditioning should stay constant on both units.
Putting it down to 17 might be ok for you, but not others. The same as putting it up.
An acceptable balance is around 22. It should regulate the temperature in the whole room and not blow hot or cold to compensate and changing it on one will not regulate the temperature in the whole office.
The fan angles can be changed if it does blow directly on to someone and they are uncomfortable.
Speak to your team members if they are messing with the units.
If there are any issues with this, come and speak to me.
Many thanks,
Andy