A rule relating to KERS in formula one is "poorly written", according to a supplier.
"There is a poorly written rule," said Italian company Magneti Marelli’s motor sport director Roberto Dalla.
The cost-saving rule stipulates that no more than EUR 1 million can be paid for the KERS unit supply, and then an additional 4 million on research and development.
"It was not clear whether this five million was for the global solution, or for each individual team.
"Maybe someone said it was a figure tied to the teams and, therefore, has set up their solution with 15 million," added Dalla.
It is believed the basis of the Magneti Marelli KERS is being used by Ferrari and Renault this year.
Mercedes is another KERS manufacturer for 2011, supplying units to Mercedes GP, McLaren and Force India.