question about metering for flash and ambient

Recently picked up an L-478D meter. Previously anything I did was chimping.

One thing that's not making sense to me is how the flash contribution can change slightly, but the meter doesn't change it's ambient settings.

For example I had a meter reading of F8, 1/60 ISO 100 and had my flash contribution at 10%. I wanted to get that to 20% so I moved my flash about 10 inches closer (forget about quality of light for a second). This got me to 20% and the meter didn't change the ambient settings. Picture looked fine.

Did the meter not adjust ambient because 10%-20% is only a tenth of a stop? I have my meter set to 1/3 stops.

The ambient wouldnt change in that setting. The percentage would because the flash is more powerful because its closer. But the base ambient doesnt change untess the sun gets brighter or darker. RE reading that with an eye toward the thought you might be using the wrong terms. Did you meant the total exposure didnt change?

Yes, the total exposure didn't change. Just the flash % on the meter. If I moved the flash another foot or so closer and got to 30%, the meter reading did change by a 1/3.

I think you found the issue, a 1/10 change in the power is less than the meter will indicate when set to thirds.