getDisplayGrandTotal - double tax

/** Returns the total from the cart, including tax/shipping. */
    public BigDecimal getDisplayGrandTotal() {
        return this.getDisplaySubTotal().add(this.getTotalShipping()).add(this.getTotalSalesTax())
                .add(this.getOrderOtherAdjustmentTotal()).add(this.getOrderGlobalAdjustments());
    }