so, that study was about comparing three different machines.
this is from the same study, using a different machine - and is closer to the values i got from the local diagnostic.
the takeaway is that these machines are doing something rather crude and that, while they may present small standard deviations, they're also operating in a substantive amount of error. you should approach this as a starting point and use some caution.
so, i should follow through with the blood tests, but be a little more relaxed about it - it's probably fine, and there's probably not much i can do, anyways, besides make sure i'm walking in addition to bicycling.