Max Visa Extension

[tier2uk]

Hi Immigration Experts.
I need a clarification on my Visa Extension.
I had "Tier 2 ICT Established Staff Visa" valid from May-2010 till May-12. I was in the UK only for a few months and moved back to my country in 2011.
I then changed my company and moved over.
My new employer sponserd Tier 2 ICT short Term CoS in Aug 2012 which was refused by UKBA quoting that application was made with in 12 months cooling period. So new application was made in Tier 2 ICT Long Term category which accepted by UKBA. I am currently in the UK, my visa is valid from Nov-2012 till Nov-2013. I am looking for further extensions. Could you please let me know the maximum period till which I can apply extension for?

I read few comments in internet and was not sure if I can apply extension till Nov-2015 or Nov-2017?

Comments from the internet:

Extension applications under the Tier 2 ICT category will be granted periods of leave as follows:
Up to a maximum period of 12 months if extending in the short term ICT category
3 years if your last visa issued was as an ICT work permit holder
2 years if your last visa was issued before 6 April 2011 as a Tier 2 ICT migrant
2 years if your last visa was issued from 6 April 2011 as a Tier 2 Long term migrant
Important information
As a Tier 2 ICT migrant you will be permitted leave in the UK for a maximum period of 5 years. After this period you are expected to leave the UK and serve a 12 month cooling period. You should note that the ICT route dues not lead to settlement in the UK unless you have spent a continuous period of leave in the UK as an ICT migrant under the rules in place before 6 April 2010 or as a qualifying work permit holder for a period of 5 years.