There is something seriously adrift there - it isn't '400kg more' is it - you must also have burnt your 'contingency' as well? That I assume would be around 5-600kg - ?guess? You are looking at an error of something around 10%? I'd really be concerned! The 'early' descent to 360 would be almost insignificant. One way to waste fuel in flight, of course, is excessive use of v/s on the descent, early config., mis-judged descent point amongst others.
I don't see that in essence this has anything to do with 'new policies' really. I suggest you keep on ordering that extra until you get this sorted out.
