Yup, there’s definitely cases where my Tacx Neo 2T significantly over or under performs the power target, and it’s entirely due to gearing and cadence. I have a MTB on my trainer, so in the lower gears and with a low cadence, it can often undershoot moderate power targets. Much more rarely, there will be the opposite case, where a high gear and cadence causes the trainer to overshoot. I almost have to go out of my way to induce the overshoot, whereas the undershoot can happen fairly often in the lower half of my cassette.