Dominant Mercedes is unapologetic amid increasing pressure to agree to an engine 'unfreeze' for 2015.
The new constructors' champions came under fire recently when Red Bull's Christian Horner claimed Mercedes went back on an earlier pledge to agree to relax the sport's tight restrictions on in-season engine development.
"Sometimes you have to reset your own interests and do what is best for the sport," Horner is quoted by Auto Motor und Sport.
What are Mercedes afraid of?
Given Mercedes' utter dominance in 2014, the consensus among the German marque's rivals is that at least one mid-season engine performance upgrade should be allowed.
Horner said: "Our opinion is that it would not be much more expensive, and it will not affect the customers.
"This technology is still very new, so it would give everyone the chance to sort out their problems.
"Our (Renault's) power deficit to Mercedes is so big that we cannot erase it overnight. What are Mercedes afraid of?" Horner asked.
"Nico Rosberg showed with his drive through the pack in Russia how superior that package is. They should not be afraid of competition."
Coming upgrade and no excuses
Mercedes F1 chairman Niki Lauda, however, is unapologetic about the team's new position amid the increasing pressure.
"If it really is the case that we now think differently than we did in Singapore," he said, "then I say that we made a mistake.
"We did our sums again and concluded that we cannot deliver the same for all of our customers, and especially not at the same price, as is required by Bernie (Ecclestone)," Lauda revealed.
Italy's Omnicorse claims Mercedes is preparing to make a bold step forward for 2015, when the existing F1 rules allow engine manufacturers to change up to 48 per cent of the 2014 design.
The report said Mercedes has developed with partner Bosch an upgrade of the turbo pressure to a maximum of 5.00 bar, as allowed by the regulations. Omnicorse said the 2014 turbo is limited to little more than half that figure.