The figure was confirmed by Guennadi Saienko, representing the race promoter Omega Center.
"It (the original figure) was a rough calculation, not taking into account many of the necessary requirements of the designer, the company Tilke GmbH, which has supervised the construction," he said.
It had also been claimed recently that an organisational dispute between the promoter and Russia's sanctioning body had meant a key FIA race application date was missed.
But Dmitry Erofeyev, also representing the promoter Omega, said Sochi will be on the 2014 calendar.
"When the calendar is published, you will see our grand prix there, even without an asterisk," he said.