This is directly from your article:
From these calculations, we realize the environment (mainly nutrients) can only change about 2 centimeters for a given offspring's height in this Chinese population. Does that mean that no matter what happens in the child's environment, the height can never change more than this? Can special treatment and nutrient supplements increase the height further? The answer is yes. The most important nutrient for final height is protein in childhood. Minerals, in particular calcium, and vitamins A and D also influence height.
Read that again? "Can special treatment and nutrient supplements increase the height further? The answer is yes."
It goes on to say that heritability differs depending on the population observed. The numbers are quite arbitrary, 60-80% genetic (yes, only 60% in some cases) and up to 20-40% environmental (wow almost half is due to your habits and nutrition!).
They even added the "Can special treatment and nutrient supplements increase the height further? The answer is yes." to say that their numbers don't mean that much after all.
You're only in high school, so I forgive you for not having a critical mind when reading scientific articles. In college though, cherrypicking is a no-no. Read the goddamn whole article, and understand the limits of the study.
HGH and other 'miracle treatments' won't help.
This was even addressed in the study:
"In addition, although diseases of childhood can inhibit ultimate stature, human growth hormone treatments can remedy such growth defects. Height accelerated by such treatment or special supplements, however, cannot be predicted based on heritability. There are two reasons: first, heritability has not been estimated in a growth hormone-treated population. Second, genes and growth hormones can interact synergistically to affect height, i.e., their effects may not be simply adding to each other but could be multiplying the ultimate effect."
Basically, conclusion of this study is: we still don't know how much genetics plays a role in height, confirmed by "Can special treatment and nutrient supplements increase the height further? The answer is yes." If their model was true, it would encompass all data, not just those that fit their hypothesis. Basically, their model works on those who have average life habits (they didn't isolate for those confounding factors), but couldn't explain those who have better or worse life habits (sleep, nutrition, exercise).