Engulphing patterns - Japanese candlesticks

On April 6th and 7th there was a bullish engulfing pattern showing that the trend was changing into a bullish environment.
The support shows the lowest amount it may return to to be purchased again.
Support= 4.02980

The next one was on April 11th & 12th, bearish engulfing pattern.
The resistance shows the desire to get it higher.

on April 17th, there was a doji. This would have indicated that the trend was ending. But, since we knew the support was 4.02980. That it most likely wasn't going to change for about .07 points.

I am understanding why Mr. Nison says by the time we see a change in the trend (get confirmation) it would have been too late to buy. But, wonder if this was stock would this engulfing pattern be suited for short selling?