Magento 1.7 Product with Options and Tiered pricing showing wrong percentage discount (100%)

This was bugging me at work today, found the answer at Stack Overflow

http://stackoverflow.com/questions/13504056/magento-tier-prices-class-declaration-for-tier-price-in-buy-x-for-y-javascri/16022796#16022796

Essentially, when you have a product set up for tiered pricing everything works great until you add custom options to the product.  Then instead of saying "25% off" it just says "100% off"

The solution (in case of link rot)

Edit The View File

Replace lines 34 - 34 which should read as follows:

$_product = $this->getProduct();
$_tierPrices = $this->getTierPrices();
$_finalPriceInclTax = $this->helper('tax')->getPrice($_product, $_product->getFinalPrice(), true);

With this:

$_product = $this->getProduct();
$_tierPrices = array();

foreach($this->getTierPrices() as $index => $info) {
    $_tierPrices[$index] = $info;
    $_tierPrices[$index]['formated_price'] = str_replace('class="price"', 'class="price tier-'.$index.'"', $info['formated_price']);
    $_tierPrices[$index]['formated_price_incl_tax'] = str_replace('class="price"', 'class="price tier-'.$index.' tier-'.$index.'-incl-tax"', $info['formated_price_incl_tax']);
}
$_finalPriceInclTax = $this->helper('tax')->getPrice($_product, $_product->getFinalPrice(), true);

And save your file.

Javascript Update

At this point your tiered price will probably be displaying NaN%, we need to let the javascript functions know of the change and fix a looping bug.

Open (and backup)

/js/Varien/product.js

Replace Lines 757 - 769 which should look like this:

$$('.benefit').each(function (el) {
    var parsePrice = function (html) {
        return parseFloat(/\d+\.?\d*/.exec(html));
    };
    var container = $(this.containers[3]) ? this.containers[3] : this.containers[0];
    var price = parsePrice($(container).innerHTML);
    var tierPrice = $$('.price.tier-' + i);
    tierPrice = tierPrice.length ? parseInt(tierPrice[0].innerHTML, 10) : 0;
    var $percent = Selector.findChildElements(el, ['.percent.tier-' + i]);
    $percent.each(function (el) {
        el.innerHTML = Math.ceil(100 - ((100 / price) * tierPrice));
    });
}, this);

With this:

//
// Code fixed to prevent the redundant inner loop and to use actual tiered pricing in calculation
// It also takes the optional price variants into consideration (eg: +£2 for a blue tshirt)
// Note: I've made this comment deliberately large, to keep the line numbers in sync
//
var parsePrice = function (html) {
    return parseFloat(/\d+\.?\d*/.exec(html));
};
var container = $(this.containers[3]) ? this.containers[3] : this.containers[0];
var price = parsePrice($(container).innerHTML);
$$('.percent.tier-' + i).each(function (el) {
    el.innerHTML = Math.ceil(100 - ((100 / price) * (this.tierPrices[i] + parseFloat(optionPrices))));
}, this);

Again the link... http://stackoverflow.com/questions/13504056/magento-tier-prices-class-declaration-for-tier-price-in-buy-x-for-y-javascri/16022796#16022796

Thanks to Tr1stan and well done for finding this!!