Hi

There is a development of a "bridge" sonoff for OpenHab on github https://github.com/delid4ve/openhab-3.x-sonoff/blob/main/README.md

Download Just copy the jar files into addon @ openhab. I use 3.x but 2.5 exists as well.

Click things and + and it will appear in the top.

Iammeter bridge is available via installing more bindings (just have to find the IP - win10 I use angyip  - tools - scan TCPIP)

Generate things generate items - I generated a point as well using power without the w for watt) generate a rule

Rule - when the status of Iammeter changes (power)  then (execute a script put in directly)

-------- brutal test script -----------

power_check = 1;

realpower = itemRegistry.getItem('Powre_n_w').getState();
if (realpower < power_check) {
events.sendCommand('Sonoff1_Switch', 'ON');
print(realpower);
print('On');
} else {
events.sendCommand('Sonoff1_Switch', 'OFF');
print(realpower);
print('Off');
}

Have fun 

M

PS Powre_n_w  is the point / var to get power as a number only