If you want to see a more accurate fuel estimation then use the following key strokes on the MCDU:
NAV - NAV IDENT - MAINTENANCE - NEXT - SETUP - ENGR DATA - FPL WPTS - NEXT (with arrow key next to it).
By then pressing the NEXT/PREV keys the cursor will move through the stored flight plan route and show fuel to the nearest KG at each waypoint and destination.
Remember that it only calculates on current groundspeed for the entire route.