I have changed some things now though was going to enter them in 1 by 1 as I couldnt get it to work.
Check the NI one when you get it that works out a little odd too :)
BTW to give an example of this in action
3 items in the cart (using Norther Ireland (NI) as the postal setting.
Weight exactly 31 kilos
so equates to
1st 15 kg = 26.95
16 kg at 1.15 per kilo = 18.40
Total = 45.35
Ecart = 39.35
I must admit Im lost on that.