When a controller is set up as remote controller, it does not run its own programs. It only listens to the master controller. Conceptually a remote controller mimics a physical extension to the master controller (like an expander), but it’s not hardwired directly to the master controller. So the water level on the remote controller is irrelevant. Only the water level on the master controller applies. The master controller sends command to the remote controller to turn zones on and off, and those commands carry the specific zone run time.
If you want the remote controller to apply its own specific water level, then you cannot directly use the default master-controller feature. You can either modify the firmware to implement what you want, or you have to write an external script to send command to the remote controller.