The decision was made pre-season to put little effort into developing the VF21, which itself was largely a carry over of the difficult VF20 raced by the team in 2020.
By and large, that has resulted in Schumacher and Mazepin squabbling over last and last-but-one both on Saturday and Sunday afternoons.
It's also seen the pair make their fair share of mistakes, with the team's Russian driver quickly earning the nickname Mazespin for his frequent blemishes.
Steiner suggests that those are beginning to be ironed out, however, as the season wears on.
“Making less mistakes, that is where they're developing most,” the Italian said when asked how his drivers were coming along.
“We saw overtaking [in Silverstone], they fight but they don't run into each other, so it's all small steps.”
Earlier in the season, Schumacher and Mazepin had a close encounter at the Azerbaijan Grand Prix.
In the run to the chequered flag, the former used the slipstream to move beyond his team-mate, who looked to move and crowd the German against the barrier at near terminal velocity.
In Hungary, a mistake in final practice saw Schumacher make heavy contact with the tyre barrier to eliminate himself from qualifying later in the day.
He then recovered with a strong performance on Sunday, racing the likes of Max Verstappen and Lewis Hamilton for a time as they worked their way forwards after early drama.
Steiner also suggests his drivers are getting used to life off-track, too.
“In general, they get accustomed to the life as a Formula 1 driver,” he said.
“When you get into it, it's all exciting but then you realise pretty quickly that it's actually hard work and a lot of dedication and effort.
“So they are all on that side. I think we're in a good way.”
Formula 1 returns from its mid-season break next weekend with the Belgian Grand Prix.
Following a double-points paying result in Hungary last time out for Williams, Haas is the only team without a point in 2021.