Field help (FLGEXTANT) 

When it is activated, this indicator is used to request the reversal of the totals at the beginning of the financial year by transferring them on the first event of the current financial year. This mechanism is then used to reverse these accumulations in accounting via the posting of the events rather than the creation of MO.
To do so, at least one cancellation event must be generated during the current financial year.

SEEINFO The posting or not, of these accumulations will be done depending on the setup of the entry type and automatic journal used.