@fido
Ok… try this…
"Power Speak"
Thought it better just to create a new app rather than try to reconfigure the old one 
In your case… if you set the watts level to 15 or 20 then it should work ok.
If the power goes above the set level it should speak & turn on a switch (virtual?) , if below it should turn the switch off
I have also configured a delay between messages (in case of multiple triggers)
I have tested this a couple of times with various settings and it seems to work well.
HOWEVER… I have only tested it on IOS so don’t know how it will behave with an Android device as I don’t own one
Logging is probably best left switched off unless you need it
I hope this works for you
Andy