CSS: Strike-through not centered through the text

We are using strike-through to actually show oldprice vs new price for a product.

If you open this link, at the bottom of the page, we have a product on sale. http://www.gkelite.com/Gymnastics-Shopby-GiftoftheWeek

The strike-through for the old price is not centered vertically for the text. Can any one help out as to why it's happening?

I found a solution for it utilizing psuedo elements http://jsfiddle.net/urjhN/

.strike-center {
    position: relative;
    white-space: nowrap; /* would center line-through in the middle of the wrapped lines */
}

.strike-center:after {
    border-top: 1px solid #000;
    position: absolute;
    content: "";
    right: 0;
    top:50%;
    left: 0;
}

However this technique fails if the text is wrapped between lines, the line would be centered among those lines.

It seems to work among all major browsers; for IE7 (and prior) you could just fallback to the classic line-through using conditional comments.