Okay, against my better judgement I hard coded the discount into the display to see what would happen:
Code:
<font class=ProductPrice>{$lng.lbl_our_price}: <s>{include file="currency.tpl" value=$products[product].price}</s> {math equation="price*0.7" price=$products[product].price discount=$products[product].discount format="%d.2f" assign=unformatted}{include file="currency.tpl" value=$unformatted}</font><font class=MarketPrice>{include file="customer/main/alter_currency_value.tpl" alter_currency_value=$products[product].price}</font>{if $products[product].discount ne 0}, save {$products[product].discount}%
And it resulted in the wrong price being displayed:
Generic Comic Book
This is a test item.
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Our price: <s>$ 25.00</s> $ 17.20