An interesting take from Heidfeld. Emphasis on the bolded part.. I never thought of this..
"First of all, I don't really know why something that, to my knowledge, until now has been perfectly legal is changing in the middle of the season," said Heidfeld. "But that's the way it is and we have to work with it.
"I'm very interested myself in finding out how that will affect us, because nobody knows. You can guess and make some assumptions, but I don't know. I hope that it will somehow benefit us, but it's very hard to know what effect it will have on us and the others.
"For here, the fact that we are not allowed to change settings between qualy and the race is, for me, going a bit too far in what we can and cannot change. For example, we wouldn't even be allowed to change the pitlane speed limit between qualy and the race, so if we saw that we were a little too quick during qualy we would not be allowed to change it.
"That's why it is too far. In the past we have been able to change the differential and make some small adjustments between qualy and the race but that is not allowed anymore. It's not a huge thing, but I don't understand it.