Using a dynamometer w-o a wind tunnel, is inaccurate simulation of usage

in a warm / hot climate, because @ high rpm, vehicle will be moving @ high speed : the air cooling received by battery + alternator + inlet manifold ( usually heated by radiator coolant ) + exhaust manifold & pipe & muffler will increase torque. Only in a wind tunnel with air flow @ the same speed as vehicle would be @, can simulation of usage be accurate.

I removed my bonnet's 3 rubber seals & small front grille to let in & out more air : in 28 - 30C air I found that @50 kph, torque rose 5%, @90 kph torque rose 10%, I think @110 kph torque incr will be >10%. E.g. BMW's oil sump has grooves for air cooling ( mine does not ), so the impact of air flow on such a car must be even bigger in a hot climate when its oil is hot.

The manufacturer of your car spent good money putting those three rubber seals there. They had a reason to do it, and it probably has to do with keeping the thing cool at LOW speeds, or sitting still and idling, not at high speeds. Those seals and their baffles act to keep the hot air coming off the radiator from circulating around and getting back into the front of the radiator. Serious overheating can result. When I was a kid I had a 1962 VW Beetle. I bought it with a busted crankshaft, and bought another engine and stuck it in. I left off all that darn sheetmetal around the back of the engine "to let more air circulate," and ended up with a really hot engine. My wise uncle told me that auto engineers aren't allowed to spend money on stuff that won't make the car run better or last longer (until it's off warranty, at least), and that therefore those bits of baffling were probably rather important. Second-guessing the engineers without all the information can lead to unanticipated problems.

Dan