During the current month, Float will take the higher figure from each cell, so this could be budget or actual.
When you click on a month heading, it opens the column and you are able to view the actual vs budget. If you have groups, Float will add up all the actuals and all the budgets within each group and show the total of the group as actual of budget.
If you close the column (by clicking on the heading for a different month) you will see the highest possible outcome, which is taken as the highest figure from each cell. Meaning the closed total can be a combination of both budgets and actuals depending on the makeup of the categories.
When calculating the total cash out figure, Float will expand each group and look at the individual cells within, taking the current highest figure from each cell, to calculate the total. This is to make sure we aren't filling budgets with actuals from other cells.
So for instance, where the actual is higher than the set budget, this can cause the figure to be different, than if you just added the higher figure from each overall group.