Franciscka: I'm glad you like the concept the Bank has adopted.
Zahid: since the extreme poor are part of the bottom 40%, any policy or program which reduces extreme poverty will also necessarily boost the incomes of the bottom 40%. So it's difficult to see a case of an actual conflict between the two goals.
That said, it is easy to imagine cases where the situation of the bottom 40% might improve with little change in the circumstances of the extreme poor (in countries where the extreme poor are a relatively small portion of the population.)
One question faced by the Bank is the relative weights to place on the two goals. This will have to be decided country-by-country. I think in practice we will see an effort to ensure that a substantial portion of the Bank's funding goes to projects that will credibly help reduce extreme poverty (in countries that have extreme poverty.)