Here's a puzzler that has stumped this chump. I have a facelift 2016 S75D fully optioned, including air suspension. My normal daily commute is a 14 mile one way mix of 65 mph highway, 50 mph state road and a little stop and go with moderate change in elevation. In clear temperate weather i normally average from 280-300 kWh/mi for the most recent 30 mi, depending on traffic and how exuberant I am with the accelerator. While dong my Costco run last weekend i noticed that my usage was over 300 kWh/mi and climbing even though the ambient temp was about 80 and dropping. This continued during my commute Monday and when i returned home the display showed 350 kWh/mi. I have never seen usage this high. All Monday night i racked my brain to understand this. No indication of low tire pressure. I had turned off AC and heat. No jack rabbit starts. And then i remembered that I had left two 40 lb bags of cat litter in the trunk. So I removed them yesterday morning and, presto, by the time i returned home my usage had dropped below 280 kWh/mi and it continued this morning. Can this really be the cause of such a significant increase in consumption? i assumed that the air suspension would level the car.and 80 lb wouldn't matter. The only thing i can think of is the weight was all the way in the rear on the passenger side. Perhaps the air suspension could not level the offset weight and the asymmetry destroyed the laminar flow. Any ideas?