If the on and off codes are different, then it should be fine, I may have mis-read your original post. As I said firmware 2.1.6 auto-refreshes RF signal to make sure the outlets are in sync with the controller status. For example, if the station is ‘off’, then the firmware sends ‘off’ signal every few minutes to make sure the outlet remains off. In the mean time if you trying to manually switch the RF socket on, after a few minutes OpenSprinkler will turn it off due to the refreshing. So I would recommend always using OpenSprinkler to switch it on/off.
The firmware updater allows you to roll back to any version. Before updating the firmware, there is a drop-down list where you can select the firmware version.