@JustEnoughDucks @EarMaster I'm not the original poster. I have seen lab test results supporting the LOWER water usage claim in ECO for common devices.
According to my own monitoring via smartplug, my own dishwasher uses about a 20 to 30% less electrical energy when in ECO mode as opposed to AUTO mode. It is a Bauknecht, which is likely very similar to your Bosch device in many ways (Bosch, Siemens, Bauknecht household devices all being manufactured by the same company...).

I can only measure the electricity directly. For the water consumption I rely on the values provided by the user manual.

I am well aware that Eco is supposed to be - well - more economic and maybe eco-friendly, but everything I read and could measure about my specific model indicate the opposite.