There is no concern about contamination from re-filling old bottles.
That works! You sound pretty particular about the quality of the oil changes done on your car. I am also particular, which is one of the reasons I do my own oil changes. The other reason I do my own oil changes is that I'm cheap. Doing my own oil changes not only saves me a buck or two, I can do it in less time than it takes to drive to the dealership or a quick lube place (the dealership happens to be closer to my house and open until midnight), and I can do it whenever I happen to be free.