During winter testing, eagle-eyed experts spotted the Williams solution on the new FW35's brake duct area.
Actually, the original idea was Red Bulls. Last year, the FIA ruled that the reigning champions were using the brake ducts as an aerodynamic aid, by channeling airflow through the wheel with the rim, hub and nut all playing a role.
Williams, however, modified the concept for 2013, making it legal by ensuring the exit holes for the airflow are stationary and therefore not constituting a banned moveable aerodynamic device.
Red Bull tested the Williams idea during practice in Bahrain on Friday.
The new solution was fitted to Sebastian Vettel's car only.
However, Schmidt wrote: "Williams is not sure its solution has created more problems than benefits.
"The air passing through the axle is on the list of possible sources of the problems with the (2013) car."