The website is goofy.. .not sure how you can say option pain is at 5975 when those strike prices are not even available on Nifty.. so i would not give much importance to the chart shown there... apart from that, the calculation looks similar... did you find any discrepancy in the formula?... its in the sheet itself
The formula's are shown in the website
http://www.marketcalls.in/futures-and-options/option-pain-charts-for-nifty.html
The formula's are shown in the website
http://www.marketcalls.in/futures-and-options/option-pain-charts-for-nifty.html
http://www.4shared.com/file/JqpCjBr6/max_pain_calculator_124.html