Field help (AMKRANG) 

Specify the entry range. The blocks will be entered in the order of ascending ranges.

Used to define the order of entry in the sections : in ascending order of the ranks when advancing by Tab from one field to another.. In addition, it is used in programming to identify a section. For example, to display all the fields in section 10, write :        Affzo 10         
It is therefore strongly advised to not modify the rank of the section in the screen definition.