Russell landed his maiden pole in Hungary and chased teammate Lewis Hamilton home for a 2-3 result, but only after the mechanics had turned the cars "upside down" following a lacklustre showing during Friday practice.
Despite having the summer break to analyse the data on the W13, that inconsistency carried over to last weekend's Belgian GP, when Russell was only eighth fastest in qualifying.
That was one spot behind Hamilton, who was eliminated in a first-lap crash with Fernando Alonso, before Russell was helped by grid penalties on the way to an eventual fourth.
Speaking on the Thursday of the Dutch GP weekend, Russell affirmed that Mercedes still struggles to understand what it takes to fully unlock the W13.
Russell said: "It's definitely been a bit of a theme for us this season. We're still yet to fully understand why we have such a big swing, to be honest.
"The swing is probably less compared to Red Bull, but when you look at it compared to the midfield, we are often being outqualified by an Alpine or a McLaren.
"I mean, even Alex [Albon, Williams] was very close to outqualifying us last week. But in the race, we showed some really strong pace."
Russell rued a lost podium at Spa behind Carlos Sainz, and with the benefit of hindsight would have done things "slightly differently".
He continued: "I was pretty disappointed not to be able to get third position. Had I done things slightly differently, it would have been possible.
"But we just need to overcome our single lap struggles. On my last stint I went out pretty hard and probably didn't have any juice left in the tank with the tyres when I caught up to Carlos.
"We had enough pace to maybe manage the tyres slightly more, maybe get to him a lap or two later. But I think we've still got to be relatively happy with how the Sunday panned out.
"But we just do understand where all that performance went on Friday and Saturday."
Hamilton qualified 1.8s adrift of eventual Spa victor Max Verstappen while Russell was a further three tenths in arrears.
Asked where the major deficit was coming from, Russell lamented a lack of overall downforce.
He explained: "Global performance is one thing. Once we get to Sunday, and things are a bit more even, we see that we're still on average three or four tenths behind Red Bull and we need to find some more global downforce and maybe make our car a bit more efficient so we're not losing so much time on the straights.
"But as we said, we're on the back foot this season when we're qualifying at the bottom half of Q3 or sometimes not even in Q3 and it puts us in a very tricky position.
"Tyres have been a sensitive point for many teams for so long. We just need to find a way to get the most out of it on that single lap."
