I am not sure what do you mean, however i took a screenshot .
Basically it's a feature within Shelly 2.5 and there is another one for under power and another two identical for Channel2 (Over power and underpower).
I have managed to get the URL working when I paste the url on my browser however when i configure it under the Channel 1 Over Power or Under Power, nothing happens.
http://admin: #PWD# @ #IP of PlugS#/relay/0?turn=off
All i did was enable it, set the power consumption and click save.