The only answer that you are going to get from anyone at Honda is what is stated on the EVSE itself, 110V to 120V. If in fact the EVSE is identical, Honda could have done like some other EVSE manufacturers have done and provided a EVSE with a 240V connector, along with an adapter from the 240V plug to 120V plug. As far as I know that is the only legal way they could have provided an EVSE rated to work with both 120V and 240V. They chose not to do so either because they are not identical, or because they wanted to save a few bucks in the cost of the adapter and also testing and certification for using it for both voltages. Only Honda can conclusively answer the question which of those two it is, but I highly doubt if you will get an answer from them about it other than the standard canned answer that the EVSE is only rated for 110-120V.