Field help (FLGMODGL) 

Select this check box to modify the G/L account number according to the following next options:
Select Shorten or Lengthen.
Enter the number characters to modify.
Select whether to add or remove characters from the Right or Left.

If the character length of the G/L account is less than the number in the entry field, zeros are added to the account number.
Modifying G/L account numbers is only effective for G/L accounts that have not been assigned to a DATEV account in the DATEV G/L account assignment function.
The length of DATEV G/L account and BP account numbers are interdependent and must follow these rules:
DATEV G/L account numbers must be between four and eight characters long and must always be one character less than the DATEV BP account number.
If the G/L account number is eight characters long, the BP account number must be exactly nine characters long. 
DATEV account numbers (G/L account or BP account numbers) must always be numeric.