Your markings show the buy/sell at the peaks, whereas the rules say that the trade should be undertaken
after the ema crosses over the other side. Now the confirmation / true signal would come only after the bottom most / topmost candle is fully formed and we are onto the next candle. Often we have seen the EMA cross back below/above the BB by the time the TF gets over. Hence the trade can be taken only on the
next candle after the crossover is confirmed.
This, of course, is the issue with price action based trades, because the trader makes his move after the signal is complete, which renders him vulnerable to whipsaws
. I don't think that many of us would be able to catch the bottom most/ topmost candle, because most of us maybe thinking that the next candle would he lower/higher, so better wait till the up/down move is complete and definitely reversed, as confirmed by EMAs re-entering the BB.