The program manages the income and expenses of the corresponding month. The profit or loss will not be carried over into the following month. Reason for this is that you should be able to spot on one look if your expenses were too high in the corresponding month or not
(if the expenses were higher than the income) in order to identify financial problems right away. The cumulation over the year can be visualized under 'Evaluation' and 'Overview' (select current year).