Some DIV cross browser issues regarding product listing prices

Can any one help. Ive managed to align all the prices to bottom in their own divs as you can see in the following screen shots, by making the centreboxcontents divs relative, and the .standardprice div absolute, which sits inside it.

With the margins auto, its sits perfectly in Chrome in the middle of the box, but in Firebox and IE it sits way over to the right, and I cannot for the life of me figure out why. Any ideas? Code in my style sheet is below.

.centerBoxContentsNew {height: 210px; border: 0px solid #000000; position:relative;}

.centerBoxContentsProducts {height: 270px; border: 0px solid #000000; position:relative;}

.standardprice {
 font: bold 28px arial;
 position: absolute;
 letter-spacing: -1px;
margin-right:auto; margin-left:auto; width: 100%;
	float:center;
	bottom: 0;
	text-align: center;
	line-height: 150%;
}

Chrome:
http://www.zen-cart.com/forum/attachment.php?attachmentid=9364&stc=1&d=1308225021

Firefox & IE
http://www.zen-cart.com/forum/attachment.php?attachmentid=9365&stc=1&d=1308225081

Fixed - In the function_prices.php file where the ref for the .standardprices was, it was a <span> tag instead of a <div> tag - Once changed works fine in all browsers.