Addressing your first paragraph, I view it as 2 seperate scenario. "Right" re-entry price, now.. Would you buy in a US fund now.. I'm VERY SURE it will drop further. So what opportunity cost? I would wait rather than making a loss you know will happen and average down again. Maybe that's me.
Your concern is WHAT IF you set your targeted return too low, and you sell way too early. Thats each to their own right? Some intend to hold long term like you, someone like me like to hold 3-4 years max, and some short term. Yklooi didn't mention UT, so short term does apply here. Same goes to selling. Some drop 10% and they cannot take it, you cut loss. Some like us we average down.
Once again, I believe there is no yes or no answer here. Some may be greedy and set higher return, some may set lower. For example, last month when HSAQ was at their highest, some people may opt to lock their profit. Some may choose to hold. In the end, they profited from it while we are still waiting for it to goes back to that level.
That's why I mentioned that people can revise their intend cut lose point and target return along the way. Correct me if I'm wrong, Pink.
I follow the FSM quote advised to proceed with DCA... Applied RSP... In order to neutralize the volatility markets. Fund selected based on strength of company stocks/sector/region that fund invested.