Yes, if the input data is wrong, the simulations will be wrong.
But Newey said: "It's fair to say that some of our tools are weak. Particularly the driver-in-the-loop simulator needs a lot of work because it's not correlating at all at the moment, which is a fundamental research tool."
"Driver-in-the-loop simulator" is the problem. The simulator’s current state is not correlating with actual performance and needs significant improvement. So, the issue isn’t just with the data input, but with the simulator’s overall functionality, which affects how well the car’s performance is predicted. Which means even with good data, it might not be able to give any useful feedback on how the car will perform
FYI interview : https://www.bbc.com/sport/formula1/arti ... e7le4l5geo