Red Bull Racing boss Christian Horner says he does not understand why the FIA chose to make a move on the blown diffuser regulations midseason, rather than waiting until the end of the year.
With Horner claiming it is impossible to predict what impact this weekend's change to engine-mapping rules and the looming ban on off-throttle use of blown diffusers from Silverstone will have, he has expressed frustration at the timing.
"It is slightly confusing with the technical directive that it was not addressed at the end of the year going into next year," he said. "Why has it been done midseason, rather than like the F-duct or the double diffuser [that were allowed to remain on all season]? But, at the end of the day, it is the same for everybody and we will deal with it starting at Silverstone."
When asked whether he was worried about the consequences of the changes on Red Bull Racing's title challenge, Horner said: "To be totally honest it is impossible to predict.
"We know what benefit we see, but we don't know what benefit others see. I think in reality it will affect the front-running teams probably a very similar amount, to be honest, but until we get to Silverstone it is impossible to predict."
Horner did suggest, however, that rival teams hoping the FIA rules directive would hamper Red Bull's overall form were likely to be disappointed.
"The secret to a quick car is that there is never a silver bullet," he said. "It would be wrong to expect that this has been the sole reason behind the performance of the car, either this year or last year or the year before that. It is one of those things.
"We will deal with it; we will move on. We have some parts in the pipeline for Silverstone and hopefully we can be competitive there."