This indicator is used to activate or not the chronological control for the documents where current legislation imposes chronological control of the numbers with respect to the entry date (this the case for certain documents in certain legislations, notably Italian).
It is used to avoid a document logically dated with a date D1 being created with an earlier number than a document logically dated with a date D2 which is precedes D1 (this irrespective of the real date of creation for the document).