Edit: I am more convinced than before that your trendline errs on the side of predicting a BTC/USD rate on the low side and can lead to a premature sell indicator.
The sell signal is when price = 3*trend
I understand this but if the trend is below where it should be then the sell signal will be premature.
the trend is never below where it should be, it is just a trend. The price can be below the trend.
Sell signal level has nothing to do with current price. It is predefined. It is only a function of time and trend (sell signal happens when current price = trend price * 3)