Hi,
just looked at this... if you go direct to the application site, all vehicles seem to have the same charge. I tested pure electric and fully petrol, and all had the same charge.
However the found that you have to apply separately for the Cleaner Vehicle discount
https://tfl.gov.uk/modes/driving/cc-cvd-before-you-begin?sourceRoutingKey=discounts-and-exemptionsI haven't actually tried as I'm not planning to drive into central London, and registration looks pretty complicated and you have to setup an account 1st.
good luck