Please can you make it possible to select multiple Thermostat Schedulers in a rule-5.1 action when selecting the thermostats by app name (not by device). For comparison, here's the setting for selecting by app name:
Even with the multiple thermostat selection, it will still only work against a single Thermostat Scheduler instance. Rule is not setup to handle multiple instances in a single action. However, you could just copy/paste that one action for each instance that you want to adjust, and edit those copied actions to set a different instance of Thermostat Scheduler.
Changing this over from single Thermostat Scheduler to multiple won't happen, as this action is already very complex.