Peter Sauber has said that the FIA were partly to blame for his team failing to secure sixth in the constructors' championship this season.
Sauber were hit hard by the arguments surrounding the blown diffuser this year, having shelved development of the part when the governing body announced that it was to be banned.
However, the decision to then backtrack on that ruling and to allow the technology to remain in place for the rest of the season meant Force India were able to steal a march on the Swiss outfit and secure sixth in the championship come the season's end in Brazil.
"For all the joy we have not forgotten that we wanted more," Sauber wrote in a column for German publication Blick
. "At mid season we were solidly in position six, but we soon fell behind Force India. The reason is the blown diffuser and the so-called 'off-throttle-blowing'.
"We stopped this development after the FIA announced the ban. That proved to be a mistake because the FIA went back and bizarrely allowed this technology again. It got us badly on the defensive into the second half of the season.
“Those with the systems optimised their advantage, achieving much more than a second per lap."