I have three machines running ZISS. Their expiration dates vary from July 2008 to January, 2009. If I buy the two-year, three-license renewal package, does that add two years to each expiration date, or do I get two years from the time of purchase, the time of installation of the first one, or what?

Operating System:Windows XP Pro
Software Version:7.0
Product Name:ZoneAlarm Internet Security Suite