replied directly :)
Hi there - found this issue which is the exact same as mine but saw that the reply was a direct reply - anyway you can post a solution public?
Hello there! Apologies for delayed reply. When creating a budget you have an option to tick "Rollover" feature which will cause one budget period allowance to be affected by the previous allowance. You should enable this option when creating your budgets.
Then you can set Carried balance in the budget creation window and you can set it to a negative amount. For example you're creating a budget with monthly balance of $100 but the current balance of the budget is minus $110 because you've overspent the budget by $10. To reflect this, enter -110 as the carried balance so that the resulting budget will have minus $110 balance.
Next month it'll have plus $90 budgets balance ($100 original allowance minus $10 overspent last period).