Mercedes trackside engineering director Andrew Shovlin has provided an explanation for Lewis Hamilton's disqualification from São Paulo Grand Prix qualifying and suggested a "layer of paint" would have made the DRS legal.
Hamilton was fastest in qualifying at Interlagos last week before being scratched from the session after the DRS failed scrutineering.
It was revealed that the slot-gap when the DRS opened exceeded the maximum distance of 85mm, with Mercedes challenging this had been due to damage caused on-track, with deliberations extending over 18 hours despite the black-and-white nature of the technical regulations.
Describing in detail the process of the stewards' ruling, Shovlin said: "The issue is specifically the DRS is only allowed to open to 85mm and they power the car up and they have a jig that measures that displacement.
"We were under the 85mm but another element of the technical directive - not the regulation, but the technical directive - to judge that applies load.
"It was that load that popped the go-gauge through the flap. Now that is a test that is one of the most common tests that is done on the cars.
"That very assembly had been tested and the FIA and had previously passed. We test these every time they go on the car and it had passed.
"What we could see was some play in that flap that was the cause of the failure. It was fine over about 90 per cent of the width of the flap but there was one area where this play was allowing it to pop through.
"Now, because we then changed that wing, the one with the fault has been held by the FIA all weekend so we would expect to get that back when the cars are released.
"Therefore, we haven't had the time to do the investigation to get to the bottom of it. What we are confident is that it has developed a problem at some point in its life with the wear and tear of running on a car.
"We are not talking big margins here, we are talking about 0.2mm, you are almost talking one layer of paint would have put the thing legal, but the technical regulations are very often interpreted in black and white situations and it was that interpretation that led to the unfortunate demotion from pole to the back."
Why stewards' verdict took 18 hours
Max Verstappen was fined for touching Hamilton's car under parc fermé conditions, with that incident adding another layer to the scrutineering process as it was the same part of the rear wing under scrutiny that the Dutchman had touched.
Explaining why he thought the decision to disqualify Hamilton took so long, Shovlin commented: "It was complicated a little bit by the fact we weren't the last persons to touch the very element that was under suspicion, it was Max in parc fermé, the stewards wanted to look at that footage.
"I think the other element that complicated it, ordinarily when there is a fault, when something is broken, you can investigate, teams are allowed to fix problems for retesting.
"For instance, if you had a bib and you clattered over the kerbs and snapped it, it wouldn't pass the load-deflection test and it is not uncommon that the FIA would have let a team change the broken parts, retest it just to make sure in a normal condition, a part passes.
"That was perhaps another factor that was bouncing around in the background but ultimately the stewards ruled on it, we need to get on with it and there is not really much point in dwelling because once we had that ruling, we didn't really have a lot of come back."