As Carl suggested, the numbers are less important than they sometimes seem. On a vinyl pool, if your water is clear, and your pH is not too low, and you aren't adding copper . . . you're not going to damage your pool.

The Taylor TA test is probably the most accurate one you have access to -- so if you are using it correctly, those are the results you should trust. But there is room for 'operator error' any time you do a titration, whether it's with a glass buret and an Erlenmyer flask, or with a 100 mL plastic tube and 3 dropper bottles. If you want to be SURE you're doing it right, check out these videos:
https://www.youtube.com/playlist?lis...99CY_BQXE1Jx6s
https://www.youtube.com/playlist?lis...-ZRW_OFLP4jNO4

But honestly, if you'll just relax a bit, things will be easier, and you'll get better at the details.

One absolutely key point: no pool EVER runs exactly by the book. The real world is always more complicated than the 'rules', and if you try to make the two sync up perfectly, you'll go nuts. Twenty-five years ago, we were told that the IgE levels found on my then 3 year old son were impossible: if he REALLY had those levels, he'd be confined to an allergy bubble in Arizona. But, those levels were confirmed with subsequent testing, and yet he's never been confined, though I did give him allergy shots for 7 years. Twenty years ago, my pastor was told that his cholesterol levels were close to the highest ever reported, and that he should plan for a short life expectancy. He's still alive, though he did have to have a bypass 3 years ago.

Bottom line: no set of tests, even with multi-million dollar equipment, will fully describe what happens in YOUR pool. But, with practice, you can get 'close enough' with the Taylor K2006. And that's really all you need.