I believe the drawback you are referring to is down to the time frame you are trading, the anchor points =high- Low as you call them would be different on the hourly chart than i would take on the 5 Minute chart.
Correct! However not a problem as this is based on Duration or Targets that you have set. This is not a charting problem but a trading strategy issue. My style uses 3 different charts and depends on if I am scalping or Position trades or Hedged Trade with correlated markets and/or setting of targets and stops. The Trader must know only how long he/she will be in the trade and number of contracts traded. Most newbies to this style use wrong targets and stops. Note: Of course not every trade is a winner but no need for that as settings based on 70% historically winning trades will produce profits. I have a scateboard teenager who is using this system with a $3000 account and he is averaging a $100 net per day.