Great plan, we're on that too.
We simply have the EV charger on normal circuit, it appears you don't need it separate with CL type schedules here in SA, the smart meter just separates the TOU times of days, and applies the relative rates.
Maybe that's your issue ?
During a nice day we can just have it charging the sons EV free, or set (though his Tesla) to charge 0001-0559 and it all does its thing,
Tariff 33 CL so all you have on there is the EV charger ?
And there is no power to the charger at all outside that 0000-0600 ?
Perhaps it would be a good idea to contact the charger installer and ask them too ?
They have possibly come across this before most likely, and to be honest, it's up to them to make sure that the system is installed and working, even now with possible metering changes, which should have been worked out before it was put in.