Haas F1 boss Guenther Steiner fears that the team switched its development focus too early, and is now paying the price.
The team opted to stop working on improving the VF-17 during the summer, in favour of getting an early start on next year's chassis. But since the summer shutdown, Haas have been struggling against their rivals.
Last weekend in Mexico, Kevin Magnussen and Romain Grosjean ere the slowest cars in qualifying. They were even outpaced by the two Saubers.
Magnussen did manage to finish in the points, putting them just one point behind their rivals Renault in the constructors championship. Both teams have also closed up behind Toro Rosso.
But whether Haas will be able to overhaul their rivals in the final two races of the season is yet to be seen. And it might have been a different story if Haas had continued to keep improving the current car.
"We stopped a bit early, in hindsight," Steiner admitted to the Ekstra Bladet newspaper.
"We took a decision to change focus to the 2018 car because we wanted to make some fundamental changes that we could not transfer 100 per cent from this car," he explained.
"Should we have done that? I don't know."
"I don't know what the teams that further developed their 2017 car can carry over to their 2018 car," he pointed out.
Steiner added that the proof would only be seen when next year's cars took to the track in pre-season testing.
"The verdict will only come in February when we test, whether it was worth it or not," he said. "We will only find out when we see them all on the track."
"Right now we have a nice wind tunnel model with a lot of numbers."
One thing that isn't a big concern for Steiner right now is the introduction of the Halo cockpit protection device. It's mandatory for all cars in Formula 1 next year and will impact aerodynamic handling.
"To be honest, until next year, we have other priorities for practice other than Halo," Steiner said.