Hi Paulo.
From the small number of tests that I've carried out since the update I don't think the relationship between the FE attribute and MPG (or litres/km) has changed.
It is the fact that many of the the circuits are now shorter which results in less fuel being required to to complete one lap.
If the number of laps for the race is adjusted to make the full race distance the same as before the update the amount of fuel you require for the entire race will be the same.
This is the same for tyre wear, because the tracks are shorter the tyre wear percentage is also lower.
As you can see from the table below, of the 24 circuits (GB09 no longer exists) 18 are now shorter. Two are significantly longer, Monaco and Mexico and for these you should find that they now need more litres per lap than they did pre-update.