Any notional long term gains until January 31, 2018 have been "grandfathered" or exempted while calculating for long-term capital gains. So you can assume the new cost of holding your Equity Mutual Funds is the closing price on January 31, 2018. Don't forget that the exemption of Rs. 100,000 applies to all your Equity Capital Gains - across Stocks and Equity Mutual Funds and not just investment in one scheme.
