If my fading memory serves me correctly, the figure of 6% of extra fuel carried per hour is the cost on the -200 & -300 B747. Loading an extra 5000 kgs above planned fuel and carrying it for 4 hours would result in an additional
1100 kgs over planned fuel being burnt. (
5000 - 6% = 4700 - 6% = 4418 - 6% = 4152 - 6% = 3903 Kgs of original extra 5000 Kgs remaining). Stand to be corrected if my memory has failed me.
