If they prepare for a cold race now, they may be faced with warmer temps on Sunday.
This is the dilemma of the W03, which appears to be set up sensitive with regard to the use of its tyres.
Lotus GP issued a radio message to Raikkonen explaining that they expected warmer temps on race day. So I think Mercedes will be waiting until the very last minute of FP3 before deciding which direction they will go regards set up.
Also, even the though the car has no visible updates, Schumacher was still competitive on his race sim on soft tyres compared to Hamilton and Webber. And this without
DDRS.
Come race day, I think we will see what this car can really do without street surfaces(Melbourne) or climatic conditions(Malaysia) masking the cars performance.
Either that or the team has run its list of excuses(temprature excuse aside...

)