I have an ASUSTek P7H55-M LX. System Info says BIOS is American Megatrends Inc. 0402, 10/29/2010. When I visit http://www.ami.com/support/ "BIOS updates" goes to a site that wants $30. Do they not offer free updates?
It seems you're looking in the wrong place.
The ASUS Support website is better. I found a wealth of downloads at http://support.asus.com/Download.aspx?SLanguage=en&m=P7H55-M+LX&p=1&s=32.