If suppose the FCOM is not clear enough...?
Check the loadsheet TOCG vs. the ECAM GWCG: ‐ If the difference is less than 1 %, no further action is required The ECAM GWCG is reliable. ‐ If there is more than 1 % difference, check that the ZFW and the ZFCG are correctly entered in the FMS.
1.If not, revise the ZFW/ZFWCG in the FMS and compare the ECAM GWCG and the loadsheet TOCG
2.If the difference is confirmed, compute again the loadsheet using the trim tank fuel quantity displayed on the FUEL SD page For more information on how to compute the loadsheet using trim tank fuel quantity, Refer to PER-LOD-FDC Trim Tank Adjustment.
3.If the difference between the loadsheet TOCG and the ECAM GWCG is still greater than 1 %, suspect an abnormal fuel distribution. Confirm the fuel distribution with load control and compute again the loadsheet accordingly.