Gauge R&R for gloss meter

Hi,
I need your advise on the gauge R&R for plastic components. I had to do analysis for color (spectophotometer) and for gloss (gloss meter) and as for color the results are acceptable and three were no major issues during the analysis that for gloss I don't know what to do next. The tolerance od cery small - 1.7-2.5 GU, but rather standard for gloss req. I've fot really good results, sample range is ~0,1, NDC =5, but still %SV id 25,2 % and SV/toler. Is 36.5%. I can't image how I would improve my analysis to get a better score... I would have to get the same results each time...
Maybe the MSA analysis for gloss should be treated as attribute and I should the Kappa analysis instead? Did anyone have a similar problem? Please let me know if you have any experience with gloss meter analysis.

 

Gauge will be used ones per 8h. Yes gloss vary by location but for my R&R study I defined area to take the measurement.