Hi again! 
Okay, so first off, we’re mixing two different terms: correction factors and calibration factors. Correction factor is how much a unit of insulin will lower your blood sugar, just as you suggested. (Other, smarter people here at FUD, if I’ve misspoken, correct if you will). 
The calibration factor is what I refer to in this thread. It is only a thing with Medtronic, whereas the correction factor is a general diabetic concept.
This pertains to the calibration factor, and I have no idea why they choose to mention it when they do, but it appears to be completely a random bit of information some Medtronic reps offer. I think I’ve made 850 calls into Medtronic and have maybe had 3 reps ever mention it to me.
I know you’ve gotten your 670G, and I will tell you that even if you’ve never calculated it before, it might be something worth understanding now. With the old sensors, there was a general guideline of calibrations needing to occur within a range of 3 (I can’t remember if it’s 2 or 3, but that’s not a common one anyway) -8. So 3-8. I believe the vast majority of our factors naturally occur within that range, so it was never much of a problem. On the 670G, however, it becomes a very strict rule. Manual mode is more forgiving and holds a wider range of 3-10. Auto Mode, however, holds you to 8. And if you try calibrating outside of that range, it’ll tell you it’s not accepted, and if you collect 2 of those, you’re told to change your sensor. There are really two rules that are worth learning as you start out, and the other one is the 35% rule. Understanding these things can really help you avoid a lot of problems and give you a shot at getting more out of your sensors.
Hopefully you’ll jump right in and have some luck with it and never need to look at these rules again. If you find you’re struggling though, this would be a good place to start. I see you’ve joined the Honest Exchange, and I wanted to let you know you can tap me if you need anything at all. Either here or there. It can be kind of a tough transition, and I’d be more than happy to help you get some information to make it a little easier.