Not sure where you came up with that combination.
On a triple butted spokes I've seen, the elbow is the thickest, then the threads and then the middle in decreasing thickness.

Do you have a caliper/micrometer to get real decimal numbers?

You are aware the threads are rolled, not cut? That causes the major diameter of the threads to be larger than the original diameter of the spoke.

More likely you have 15/16 double butted like I use on my fronts and NDS.
AKA DT Swiss Competition.
Look for their logo on the end of the J bend.

http://www.coloradocyclist.com/dt-sw...6-gauge-spokes

What I'd do is replace the one spoke with whatever you can get and ride it for a couple months. IF you break spoke number 2, replace all of them on that side (at least) or both sides.