You need to add set analysis in every expression as follows :
=only({<DATEBON={">=$(DateLower)<$(DateUpper)"}>} BUDGET)
I used only as a function, you may use sum or whatever is suitable for your data.
DateLower and DateUpper as variables the user date selection is assigned to. You cannot use a field, as this would reduce data to the selected value only (unless it is a data island)
