Here is what I know of H1B extensions.
1. If you have a Labor Cert application (PERM or RIR or traditional) pending for more than 365 days, you can get a 1 year extension of your H1B.
2. If you have an approved Labor Cert which is more than 365 days old (ie its been 365 days since you applied) then you can get a 1 year extension. This is regardless of whether you have an I140 pending or not.
3. If you have an approved Labor and an approved I140, you will get an 3 year extension of your H1B.
4. If your Labor Cert application is less than 365 days old, regardless of whether its approved, you will have to go home for a year.