McLaren may have got it wrong when designing its bespoke rear wing for Monza, according to Germany's Auto Motor und Sport.
"If you walk up and down the pitlane you'll see that some cars have a wing on that looks like the thickness of two sheets of paper," said the team's Jenson Button.
Auto Motor und Sport reports that McLaren's is visibly the biggest of them all.
Last year, Button surprised the paddock by performing strongly with a notably big rear wing at Monza, while his teammate Lewis Hamilton - and the rest of the field - wore traditionally-thin Monza wings.
Button's decision paid off in 2010 because of the drag-shedding F-duct, which could be deployed anywhere around the circuit, with the big wing producing more grip in the corners.
But in 2011, the similar 'DRS' system for the rear wing can be used in the race only in its designated zones.
Another difference with 2010 is that with the exhaust-blown diffusers now producing much of the rear downforce, running more wing at Monza is not as beneficial in terms of the top-speed trade-off.
Williams' technical director Sam Michael, however, is not sure.