class SpendProfileTableCalculator {

    public BigDecimal calculateTotalOfAllActualTotals(Map<Long, List<BigDecimal>> tableData) {
        return tableData.values()
                .stream()
                .map(list ->
                    list.stream()
                            .reduce(BigDecimal.ZERO, BigDecimal::add)
                )
                .reduce(BigDecimal.ZERO, BigDecimal::add);
    }

}