The "Help" button is used to re-sync device(s). It does NOT modify your configuration.
I see 2 possibilities to your problem:
1) You selected the option "I want to leave this device on all the time" in the cable box Device Adjust Power Settings. This option prevents the activities (including the special "Off" activity button) from controlling the power of that device. However, the activity "Help" feature still tracks what the power state should be and will send the power command when asked.
Solution 1: Select option "I want to turn off this device when it's not in use".
This is the standard option allowing the activities to control the power.
Solution 2: Select option "There are no power buttons...". You will have to control it manually.

2) The inter-device delay for the cable box is too short and it misses the power command.
Solution: Increase the cable box inter-device delay (Device > More Options > Adjust the delays).