I think the key issue here is that you may be gauging how well something is working based on its immediate impact on the marks you're making. So, you try drawing from your shoulder, find that your control over your marks suffers, then try drawing from your elbow and find that it produces better immediate results, and thus operate under the impression that drawing from the elbow works better for you.

That is unfortunately a misleading approach, because drawing from the shoulder takes time and experience to get used to. It is very tiring initially and will often produce worse results because the muscles involved are not yet developed.

There are many situations where in order to expand your capacity to do things, you need to allow things to get a little worse (in terms of their immediate results), and generally speaking attempting to gauge how well something is working on your own (as a beginner) is not as reliable as one might want to believe, because the immediate results are the only signs they can look out for. Instead, [as explained in this comic](), follow the instructions of the resource you've decided you can trust as long as you can continue to maintain that trust, without second-guessing whether or not it's working or trying to modify it to make it suit you better. If and when a resource can no longer maintain your trust, then set it down and move onto something else.

This approach has its own issues particularly when dealing with disabilities and such, but for the majority of people who aren't suffering from additional diagnosed concerns, it will allow the processes you're being instructed to put into place their due time to have their intended impact.