Thank you @Steve52!If you already have the step-down transformer, I see no reason not to use it but being from the USA, I have no experience using 240 volts on a 200 volt rated vehicle. The step-down transformer will cause a bit of loss of power in order to perform the step-down function. Since many EVSEs work at either 120 volts or 240 volts, it would make sense that it would work at 200 volts. You should be able to verify with the specs of the EVSE you intend to buy.
That makes sense...