the easiest way to explain why your friend is making a loss is because of the following factors:
-2 times per year isn't effective DCA.
By casual observation,
2011- Jan and June's prices are the highest that year (BAD)
2012- Jan and June prices are lowest that year (GOOD)
2013- Jan is not so bad but June is costly (BAD)
2014- Jan prices is low and June is somewhere on the high side (AVERAGE)
2015- Jan and June were poor months to invest in (BAD)
You have 3 bad, 1 good and 1 average entries...
-the es3 is moving sideways for the last 5 years as compared to the more popular S&P 500 SPDR ETF.
ES3: https://sg.finance.yahoo.com/echarts?s=ES3.SI#symbol=ES3.SI;range=my
SPDR S&P500: https://sg.finance.yahoo.com/echarts?s=SPY#symbol=SPY;range=my
-The point of time in which you withdraw your DCA investment is also critical. Should you do that during a great recession, you will likely to lose less than the enterprising investors. On the other hand, DCA usually provides you less returns than an enterprising, active investor.
Safe to say, this is a bad part of the year to calculate your capital gains/losses.
TL; DR
1) increase frequency of DCA to 4 times a year
2) STI was moving side ways for the last 5 years.
3) DCA is a really long term investment strategy. 5 years might be a little short..
Not the right way to decide whether it is good or bad. It is not important to compare the performance with the rest of the year. You should be comparing the performance year over year, January of one year to January of the next year. That is the important number.

