We’ve had an Ohme home charger for a few weeks now… and I’m still trying to get my head around it ?
Essentially, you have to come at charging from a different angle if you want to take advantage of the Intelligent Go tariff: you ask the Ohme app to charge to a certain percentage (for example, if you have 50% charge, and want it to finish up with 90% charge, you ask the Ohme charger to supply 40% charge) - and then you input the finish time, the charger works out when to start (and it will warn you if your requested charge is not possible in that time frame).
btw, the nighttime EV tariff is between 11:30pm and 05:30am. Also, you should disable the Price cap on the Ohme app.