I'm not sure if the instructions are poorly worded or what but you can't rely on ANYTHING in IRS publications because they're not authoritative. Here's a link....https://kb.drakesoftware.com/Site/Browse/14896/1040-Sale-of-Primary-Residence-Used-as-Rental
So, there's the rule and the exception and you're referring to one of the exceptions that states:
A period of non-qualified use doesn’t include
1. Any portion of the 5-year period ending on the date of the sale or exchange after the last date you (or your spouse) use the property as a main home.
Seems apparent that you'd have non-qualified use for any period after 2008 if you moved into the home after it was being used as a rental but not if you converted it to rental use after using it as a main home.
