Chassis dyno’s are almost a sport now. Its about to hitting the roller with a quick shock , and yes they have learned how to accelerate, and tune for dyno power that would melt if that same tune went down the track. I would not put any stock in the power numbers correlation to track results.
Now to engine dyno’s that produce results that are meaningful and controlled. On a Super Flow dyno you set the rate that the absorption brake allows the motor to accelerate. This means even acceleration rate over the entire pull. If you dyno in a stair step pull, meaning it steady steps the rpm as the motor levels out in each rpm, the power is dramatically more power than when you set the rate at something meaningful.
By meaningful I mean to match the rate to the gear you are tuning for. On comp and Pro stock engine programs we tune for each gear.
When a motor is ramping out you can lean on it harder with compression, timing and fuel, once you get in high gear you , where the rate is much less you will have to back down.
I have spent thousands of hours on engine dyno’s , and there is reward in what I am talking about.