while what you say is correct, it has been my experience that the person working on your Mac is only guessing on how to do it and does not hold any Apple certification.
In the world that we would all like to live in, each tech would hold Apple certification along with Dell/Gateway/HP/Lenovo etc.
However because of the cost of each Apple certification exam, around $300 for the course material (on-Line), plus the cost of the Prometric exam, the normal practice, that I have seen, is to have only one certified tech who would "supervise" (watch over during the work) the non-qualified tech. In the real world, the certified person is usually the department manager, likely to stay employed for a while and thus be worth spending the money on, who is responsible for running the department and not for any hands on work.
I know of one "well known store" where there were no Apple Certified techs because the original one, the manger of the department, had quit a couple of years ago. They retained Apple Authorization because they were a "well known store" and because the old managers name was still invoked when needed.
Try asking to talk to the Apple Certified Tech and ask to see his certification docs.
Before I get flamed by every CompUSA tech out there, the above did not involve CompUSA
My advice, if you purchase a Mac from any large electronics store, is to deal directly with Apple for ALL your repair needs. In the case of a laptop, ship it in to Apple. Also, search around you town for a Certified Apple Tech.
P