No one willing to sell for loss but it will happens once you done the trade so what you will do if the price of your coin lost once you bough it?
You have two choice right,hold it until the price goes up or just buy more with cheap price and make recover from losses even if there is slight increase.
the two choices you offer are often done in trading. I use both, especially if I trade two assets at once, I will use both methods for each asset I trade. and that was proven, I was able to return capital with profit, even more.