This page is selectable from the Normal Toolbar and allows you to select the fuel loading and centre of gravity for the aircraft.
The Upper Limit for the Max Zero Fuel Weight displayed on this page is calculated from the Maximum Zero Fuel Weight set on the customer options page (or a default if the customer option is not set). It is calculated in the following way:
Max Zero Fuel Weight Limit = ( Max Payload + 10% ) + Aircraft Operational Empty Weight
  whereMax Payload = Max Zero Fuel Weight - Aircraft Operational Empty Weight.
The Upper Limit for Max Gross Weight is calculated from the value of Max Gross Weight set on the customer options page (or a default if the customer option is not set). It is calculated in the following way:
Max Gross Weight Limit = Max Gross Weight + 10%.