Asked if Renault have been surprised by the superiority of Mercedes and Ferrari with the very same revolutionary rules, he told the French-language news agency AFP: "No, we are not surprised.
"This (Mercedes and Ferrari's level) is what we wanted, and what we imagined we would achieve.
"We're not there yet, because we've had reliability problems and that caused a bit of a delay. We are about a month behind," said Taffin.
And Mercedes' F1 chairman Niki Lauda said no engine supplier is currently giving full power to its customers.
"Not even Mercedes," he told Kleine Zeitung newspaper.