Dividend growth model and cost of equity

Sir one thing which confuses me a lot and which I want to ask from you is that In Dec 2013 there was a question that Discuss whether the DGM or CAPM should be used to calculate the cost of equity. In marking scheme, 3 marks were for DGM and 2 marks were for CAPM.

Examiner answer
For DGM the examiner wrote that the DGM calculates the apparent cost of equity in the capital market, provided that the current market price of the share, the current dividend and the future dividend growth rate are known. While the current market price and the current dividend are readily available, it is very difficult to find an accurate value for the future dividend growth rate. A common approach to finding the future dividend growth rate is to calculate the average historic dividend growth rate and then to assume that the future dividend growth rate will be similar. There is no reason why this assumption is true

Studytext answer
In study text, it is written that there are number of problems with DGM. The model does not explicitly incorporate risk, dividends do not grow smoothly in reality, so g is only an approximation, The model fails to take capital gains into account, No allowance is made for the effects of taxation,It assumes there are no issue costs for new shares and It does not produce meaningful results where no dividend is paid (if d is zero, Ke is 0)

My question is that in above case, if we do NOT learn and write examiners answer in exam and instead learn and write the answer given in studytext , so would it enable us to obtain full 3 marks by learning and writing answer given in studytext?