"We've now a better understanding of the tyres, and we've shown that over the last few races. We can predict with a bit more certainty what will happen," Steiner told Autosport.
"That has been the main focus of our race engineers, to find out when the tyres work, where do they need to be temperature-wise to work. A lot of work has gone into them, a lot of deep analysis to understand them more."
The ultra-soft continues to be Haas's Achilles heel, with both Grosjean and Esteban Gutierrez unhappy with the car's performance on the softest compound in Austria.
Gutierrez described it as "a bit confusing" and "not very nice" in qualifying and Grosjean said he "cannot get 100%" as it gives insufficient warning of when grip will break away.
Neither driver used the ultra-soft during the Red Bull Ring race.
Haas Formula One drivers Esteban Gutierrez of Mexico (L) and Romain Grosjean of France smiles as they pose next to new VF-16 F1 car before the first testing session ahead of the upcoming season at the Circuit Catalunya-Barcelona
Image credit: Reuters
"That was a choice, that was not by default, because we struggle to get that one to work when it's cooler," Steiner explained.
"In theory, an ultra-soft should work when it's cooler. It's the softest tyre we have, but we cannot get it to work because we are not getting it in the window to work. Maybe it would have worked, but we didn't want to take the risk. We know what we can get away with, but we didn't want to take any risk using the ultra-soft."
Such issues are why Steiner feels it is too early to claim Haas has cured its tyre understanding problems.
"It will still be a rollercoaster for us this season," suggested Steiner.
"By no means are we perfect, and the midfield is so tight with McLaren, Toro Rosso and Force India. Any of them on a good day are faster than us, but any of them on a bad day are only a little bit faster, but the car was pretty good again in Austria, so it will help us."