Home testing is most useful determining what gives you unacceptable spikes, what you can tolerate to eat, how to mix different food and drink groups to flatten the curve so to speak, for me its a useful tool and companion. Naturally the more readings you take the greater the accuracy of the daily graph the machine creates. My unit will show me averages over the past week, 14 days and so on up to 90 days. The phone software uses this information along with other data it collects, i.e. mealtimes, physical characteristics and no doubt a hoast of other factors to translate this into a predicted HBA1C result which is surprisingly accurate but not exact. It generally reports it will be a couple of m/mols per mol less than the lab result. This is not a problem as its consistent, so by just adding two points to its prediction I know whats coming!
What I do find annoying is that I can modify rogue results in the softaware, i.e. forgeting to wash hands and testing after I have just scavenged sticky plates and dishes from my daughters bedroom, but can't in the machine. After ringing to complain they tell me they disabled the feature so people couldn't cheat!
So don't be scared, the meter is your friend, it helped me a lot when learning, now I don't use it so much as I know the carb content of pretty much anything off by heart, took me about a year. What I do know for sure as almost ANY bread is a carb disaster, well its not the breads fault, its the flour - bad news, even commercial low carb breads can only manage about 7 carbs a slice, and hence that applies to anything with flour in it. I use a low carb seeded brown bread, 1.5 carbs a slice.
May I suggest you try the carb and calorie counter paperback book, its was really useful to me in the early days as a pictorial reference, some of the listings will surprise you!