Gerrymandering or correcting an inequality?

The BBC are happily parroting the Labour line that the Conservative/LibDem coalition's bill is attempting to gerrymander House of Commons seats. This is odd as before the general election I remember the BBC admitting that the current electoral system is stacked against the Conservatives.

I looked at the BBC's own 'Election seat calculator' and fed in some numbers around the 30:30:20:10 split:
Conservatives 29.9%, Labour 29.9%, LibDems 19.9%, Others 20.2% - Labour 325 seats, Conservatives 225 seats

Then I played around with the settings such that the LibDems were stuck on 20% and Others on 10%:
To get 326 seats (the amount needed to form a majority government) the Conservatives needed 40%, whereas Labour needed 34.7% (at that level the Conservatives could have 35.3% and still be well beaten by Labour)

So the current electoral system favours Labour over the Conservatives, is that why Labour and the BBC want to keep it?