Conditions reduction

I'm calculating the displayed payment amount for an order receipt, I want to reduce those conditions to the max:

private double CalculateFinalTotal(bool hasPrommoCode, 
                                   double promoCodeValue, 
                                   double finalTotal, 
                                   double? tip)
{
    if (!hasPrommoCode) return finalTotal;
    if (promoCodeValue > finalTotal && tip.HasValue) return tip.Value;
    else if (promoCodeValue > finalTotal) return 0;
    else if (tip.HasValue)
    {
        var totalWithoutTip = finalTotal - tip.Value;
        return (totalWithoutTip > promoCodeValue ? totalWithoutTip - promoCodeValue : 0) + tip.Value;
    }
    else return finalTotal - promoCodeValue;
}