Question on H1-B 6 years calculation


I need a bit clarity on 6 years calculation for H1-B.

I got my H1-B issued in NOV-2005. I was working with the same company in US since and left US in DEC-2006 to work for the same company out of their India office (on Indian payroll). Currently, I am working with the same company in India. I now desire to join back in US. 

I would like know if my 6 years H1-B validity calculated from the date it's issued + 6 calendar years or is it calculated based on the actual time I spent in US. If latter is the case, would it mean that I still have around 5 years left on my same H1-B and can go back and work on the same H1-B for next 5 years ?

Also, I would like to know is it possible to have this H1-B transferred to another company in US if I get any offer. If yes, what would be the process.

Thanks in advance for any answers/suggestions

As per my understanding, once a petition cap is approved it has validity of 6 years during which the beneficiary can file another cap-exempt petition.

In this case, your H1B was approved almost 7 years back and I believe you are not eligible to file a cap-exempt petition. (If you were eligible for cap-exempt filing, you would have got Max 6 years minus the period of your earlier stay in US).

Now you'll have to wait till next April to file a cap-subject petition for FY2014 quota and start working in the US from 1st October 2013, and you'll get complete 6 years.