Yup. I feel this is a bit of confirmation bias on my part. I spent a lot of time on Ecommoder in the past, which is why I understood the concept of tailgate down being worse for efficiency (and why I didn't understand how a Tonneau cover could be worse.The closer a vehicle matches a teardrop shape, the more aerodynamically efficient they become. Even if the design requires the rear to end abruptly, following this shape until it reaches that cutoff point maximizes efficiency. In other words, an aerocap on the bed that extends from the roof down to the tailgate still massively improves efficiency. It's all about maintaining attached (laminar) airflow over the surfaces.