follow the follow me
I assume you mean how do you fill out the CFP fuel page?
On the far right you put down FOB and F USED at any given waypoint. At the top of the page record FOB at eng start. Take F USED away from this figure and you end up with another figure close to FOB. Take the lowest of this figure and FOB and put then in the column to the far left(left of est fuel on board...no cfp in front of me so doing this from memory). Take the min fuel figure(printed on CFP) from the number you just entered and write it just to the right. That will give you the excess fuel over fuel required at that waypoint...then just watch the trend.
It is still usable with tankering as you would expect the figure to remain constant if a Cat B CFP was used...but on the 330 you might have an excess of 10-30T instead of the more normal cat A amount of say 2-5T. This is a gross error check for leaks and to ensure you remain above 'the line' for min fuel.
clear as mud?