Multiple shopping cart discounts based on subtotal

Question

I have set up multiple shopping cart promotion rules and sometimes, more than one rule is applied. What I want is that all discount rates are applied to subtotal and not one after the other.

Example:

• Shopping cart rule of 10% discount for orders with subtotal greater than $50.
• Coupon code for 10% discount.

When I have a product of $100 in my shopping cart and enter coupon, both rules are applied. What happens: first 10% discount is applied: $100 - $10 = $90. After this, second 10% discount is applied: $90 - $9 = $81.

What I want is both 10% discount based on subtotal: $100 - $10 - $10 = $80.

I've tried setting equal priorities, but this doesn't work. Anyone knows how to fix this?

Answer 1

It can be done with the following code modification:

1) File

app/code/core/Mage/SalesRule/Model/Validator.php Copy to the local folder or create a custom module.

2) Function

protected function _getItemPrice($item)
{
    $price = $item->getQuote()->getStore()->convertPrice($item->getProduct()->getPrice());
    return $price;
}