Bill, I like to come at the problem from many different directions, and if the answer is still the same, there's a good possiblity it's correct.
Everything in photography is interconnected. A piece of information might seem to work on its own, but plug it into the bigger picture and it doesn't quite fit. Like with the reflected exposure meter reading 18%. That sounds right until you compare it with the incident meter's illuminance. A normal negative should have a density range of 1.25 to fit on a grade 2 paper sound good until you compare that to the paper LER range of 1.05 for a grade 2 paper. On the other hand, I'm happy to say the Sunny 16 seems to be able to hold up under scrutiny.
That's why I really like the constants equation. It shows the interconnection between the vaious elements involved in the photogaphic exposure by combining the constants from the exposure meter, K, the camera, q, and the photogaphic exposure, P, into an equation.
K * q = P or P / q = K or whatever variable you're solving for. K is in cd/m^2 or nits.
12.48 * .65 = 8.11