The jumper/pc method is as accurate as it gets. However, it's no more accurate than your attention span. Anything else just "interprets" the same process. More moving parts = more points of failure (hecho en chinas, btw). Spend as much or little as you want. It won't get you more function or more accuracy, really.
I have an OBD-I reader around here, somewhere (an older "gooder" one). If I can find it, I'll send it to you, and even pay the postage. IF I can find it. I always know where my paper clips are, and they always work.Really starting to sound like a paper clip is the way to go.
If it sounds like we're trying to talk you out of buying a code reader, you're probably right. Use that money to buy your wife something nice, or something....