According to the text, it's designed to prevent the problem you describe:
When the system looks for a driver to use for a particular piece of hardware, it ranks them according to various criteria. If a driver provides a perfect match to the hardware ID, then it becomes a top candidate. And if more than one driver provides a perfect match, then the one with the most recent timestamp is chosen. If there is still a tie, then the one with the highest file version number is chosen.
I don't know where this is going wrong for you but both the file version and the timestamp are things you can manipulate on that driver file. Might help, although you're in trouble if the manufacturer's driver isn't a perfect match to the hardware ID.