I'll look into the issues, at the time I could not find an easy way for the +/- control widget to process half degree increments, but maybe I can find a workaround on this.
Direct control of target temperature through scenes can be done through lua code in the scene by setting the target temperature. I'll post an example later today.
Due to outside temperatures going up last few weeks, I noticed a flaw in the current implementation of the different modes. I have a scene that triggers when I leave the house, this scene sets the thermostat mode to the 'Bespaarstand'. However, to disable the heater in the summer, I've set the thermostat to 'fixed' before on a low temperature to prevent the time program from going off. This of course gets overwritten by the leave house scene.
Therefore I either have to put extra logic in the scene, which puts an extra demand on the users of the plugin, or I can implement this in the plugin by preventing the step 'vast' to 'bespaar'. This last bit might be confusing to users though.
Which option would be preferred?