Several F1 teams have been in dialogue with the FIA over the Miami Grand Prix weekend to enquire as to whether or not Ferrari was within the tyre test rules in how it ran its car.
Teams are not supposed to change components, nor run anything that has not raced before nor run in pre-season testing, during the tests.
But at Imola Charles Leclerc was spotted running with one floor design on the morning of Ferrari's running, before Carlos Sainz switched to a different specification in the afternoon that appeared to be new.
Following questions asked by teams, the FIA conducted a probe over the matter and was satisfied that Ferrari had fully complied with the regulations.
It is understood its verdict was based on the change of floor being forced because Leclerc had caused some damage to the one he ran in the morning.
And the version that Sainz used was judged to have been run earlier in the year, either in pre-season testing or an in FP1 session.
But the FIA's decision has still not satisfied some teams, who are clear that the rule demands part needs to have been raced or used in pre-season testing.
Brown thinks the FIA needs to give teams a detailed explanation of the situation and proof of when the floor ran, to satisfy them that its policing of the regulations is rigorous enough.
"I think what's important is that we do have total trust in the FIA to police the sport, whether it's at a test or a race weekend," said Brown. "But then we also need total transparency.
"It's been suggested, or so I've heard, that maybe it was an older floor. Maybe that was the case. But I think what's important is that if that's the case, demonstrate that to the teams: just give us confidence that it's been policed appropriately in total transparency.
"We've had in the past, not long ago, an engine violation a few years back, and then there was a significant fine. We don't know how much and we also don't know exactly what was done.
"I think in today's day and age, total transparency will help the sport understand what happened, why it happened and what's been done about it."
Alpine CEO Laurent Rossi also felt that a proper explanation from the FIA would be useful to avoid any suspicions surrounding the matter.
"I wouldn't point a finger yet, because I don't know the details, so that wouldn't be fair," he said. "But at the end of the day, what we need is transparency.
"We need to know if there was something wrong or not and, if there is, what's the outcome? The most important is that we don't need a veil."
Mercedes boss Toto Wolff reckoned that the circumstances of the Ferrari test would at least ensure the topic is more thoroughly looked at in the future
"The FIA just needs to be on top of these things," he said. "It can't be that any team runs component in an environment it shouldn't be doing. And I guess if the FIA was not 100% on it, I'm sure they will be now."
Red Bull team boss Christian Horner said: "The FIA have confirmed that Ferrari ran that floor in preseason testing, so therefore it complies.
"It's for the FIA to do that police work and due diligence, because what we certainly want to avoid is because these cars are so immature, it's still very early in their development stage, that tyre tests don't turn into aerodynamic or performance development tests. That is not the purpose of those tests."
Ferrari has been insistent that it fully complied with the regulations with the floors it ran at the Imola test.
