These are the documents, for which the field MSEG-DMBUM are filled.
they were booked after a price change (in the current Period) in the previous period (for which old price is valid).
DMBTR corresponds to the value of the booking at the 'old' price. (Valid on the date of booking)
and DMBUM means the difference between this amount and the value of the 'new' price, valid from the first day of the current period.
In order to accurately reflect all this, we must have a second row with the first day of the current period creating the account date.
Further information please look at the Note 1756289