ILR- 5yrs calculation

[vivekr11]

Considering all the cost on the visa fees, I would like to ask expert here on my position for an ILR eligibility.

Situation:- I am here on Tier- 2 general. 1st visa approved on 27th April 2011. I have landed in UK on 15th may 2011. After 3 years I have extended my visa for 3 more years on same Tier-2 .

Kindly reply/advice to my questions below. Many thanks.
1. Eligibility for ILR - yes/No
2. From what date can I able to apply for ILR..?
3. Am I eligible to consider 5 years starting 27April2011 ..?
4. Can I able to use the rule- 28days period for ILR from completing 5 years ( from approved date 26 april 2016) - eligibility for ILR ~29Mar2016...?

Many many thanks in advance.