SAP Message 06410 - Sum of quantities >&< smaller than total quantity

Diagnosis
The sum of the quantities you have entered in the account assignmentitems is less than the quantity in the item.

Procedure
INCLUDE EINGABE_PRUEFEN_NA LANGUAGE EN

1173529ME51N, ME21N: MEPO 051 when deleting RE account assignment
352317ME21N: MEPO047 for contract rel.order w/o target qty