115 (C?) isn't very hot, and I think I read that they're going to change to 130. But if I correctly understand what I'm reading, the temperature of the test won't actually matter in terms of what Merc did, and was a bit of a red herring (initiated by ... who knows?). It seems the trick Merc used was to create a seperate 2 cc chamber attached to the combustion chamber by a passage only about 1 mm in diameter. At low rpms, that chamber fills up, but at higher rpms, the pressure and turbulence prevent the combustion gases from flowing into or out of the extra chamber, effectively closing it off, reducing the volume of the combustion chamber, and increasing the combustion ratio. So a test at racing rpms might catch it, while a test at merely operating temperature would not. It's very clever, but the chamber is clearly only there to satisfy geometric measurement and plays no role during combustion when operational. But yeah, it looks like the FIA, via negotiation with the teams, has closed off the loophole and given Merc a grace period to fix it. Fred has apparently told them that Ferrari will not protest the PU in Melbourne under this agreement. And who knows, this 'external chamber' thing could also be a red herring.