You are correct. I had one extra zero on the instrument, but the piston spec was correct.
The measuring instrument does ±.0001" and the hone is accurate to ±.0002" (2 ten thousandths of an inch).
I forgot to mention…there may not be a significant difference in diameter on Wisecos, but they actually measure very different from one to the next in terms of weight AS COMPARED to CP, for instance, so I’m not a big fan. Again, it’s a matter of the tolerances you’re shooting for. Wisecos work fine for plenty of people and if someone was using them we’d have them machined so they match up better before installing them. It’s just an extra step the customer would be paying for vs. buying pistons that come matched better right out of the box. CPs have never needed machining to match them up, but they all get individually weighed to a quarter of a gram just in case.