Without any evidence, I would just assume that every car company except Tesla is fudging their emissions data, and they are all fudging their MPG/range figures.
There's too much incentive there to "adjust " something.
From the article I note that MB denies using defeat devices, didn't recieve an actual notice of violation, and settled out of court. I suspect they didn't do this, but did something they'd prefer not to have revealed in open court.