And when a stock has been trending down for a while, what then is the difference between dollar cost averaging and 'averaging down'.You're confusing 'averaging down' with 'dollar cost averaging'.
'Dollar cost averaging' is purchasing at regular intervals with regular amounts no matter price movement up or down. This is an accumulation strategy, and the dividends are all reinvested to accumulate as much of the stock/equity/fund over time. Value is not a factor in this strategy as the value is what the market is prepared to buy/sell at each interval triggered.
'Averaging down' is purchasing more of the stock to lower the overall purchase price. Much like continuing to catch a falling knife (which you demonstrate in this thread IV with the likes of NWH, MCS etc).
Confusing the 2 makes your argument above flawed and not easily followed and has nothing to do with 'High Yielding Shares'.
Both positions can refer to either individual stock positions or to broader based market exposure positions.
When the market is going down, by definition, you will be both dollar cost averaging down. When the market goes up by definition you will only dollar cost average.
I really don't understand your second comment about dollar cost averaging being the accumulating strategy.
Your return under this strategy, sure is the accumulated income and the difference between starting market pricing and ending market pricing, but the overall return will be generated by:
(a) the movement in the underlying value of the investment
(c) changes in the markets pricing of that underlying value of investment.
Hence value vs market pricing.