Not complicated but complex?
You do know those two words are synonyms don't you?
High on the chest puts more strain on the shoulders, low on the chest involves the pecs more.
Thats pretty much it mate.
You want to make money from gullible young college boys then carry on filling their heads with shit.
Complex is used to refer to the level of components in a system. If a problem is complex, it means that it has many components. Complexity does not evoke difficulty.
On the other hand, complicated refers to a high level of difficulty. If a problem is complicated, there might be or might not be many parts but it will certainly take a lot of hard work to solve.
Also, Jeffrey, simply "lifting the bar, bring it down to your chest, then push it back up" so to speak is over simplifying and will give you as much result as the common gym rat (of which I think you are IMO) is expecting and receiving. For those who want greater strength, there is so much more to it.