The readings match that from Peugeot which AFAIK is based on the engine only.
The figures are power at engine, as stated on the charts and in my post.
Yes, you are correct the results are from a chassis dynamometer, which means it measures the power on the wheels. However, it is not impossible to get a rough figure for power at engine. Once the power at wheels readings are obtained, the computer would be able to calculate the power at engine. I have no idea how accurate the figure is, a question you would have to bring up with the company that does the dyno.
For me, the dyno is a useful measurement tool for tuners when they are tuning cars. It gives them a real time feedback on the effects from the changes they make on the car. It is not a 100% accurate tool, two different dyno machines would produce different results even with the same car.
What is important is looking at the before and after results, the gap between the two lines on the charts, they reflect the difference after the tuning box is installed. The horsepower or torque figures might or might not be accurate but the difference is there. People that have tried a Peugeot 308 with the tuning box installed would have already know it, the car felt lighter and more powerful. It is subjective because it is based on feeling.
This is the reason why we did the dyno runs to come up with numbers to prove or disprove that there is a difference, some sort of a objective test. Whether it has 185bhp and 275Nm or not, it is not something we are concerned about.
Let's put things into perspective, 185bhp would mean that it has more horsepower than a facelift Mini Cooper S or a VW Polo GTi. I wouldn't even believe for a minute that this is the case. I would definitely not run out waving the dyno charts in my hands and shouting at the top of my lungs that I have 185 horses. No, that would just make me look like a fool.