There will be some variation amongst the seeds of even the same pod. Which is why some ppl say that "selecting seeds from the best pods doesn't matter." I see where they're coming from, but I think is more accurate to say that doing so will give no guarantees.
With environmental factors having such profound impact on POS shape, size, cap levels, and flavors, you never can be sure of what you'll get next season. That being said, I wouldn't even consider saving seeds that came from a weak plant. There may be nothing wrong with the plants genetics; it is very likely that it was weakened by environmental factors: poor conditions, pests, disease, my own stood mistakes. The genetics might very well be great, but why risk it, of you have strong plants of the same variety to save seeds from?
I also think it's best practice to select seeds from only the "best" pods. While there are no guarantees, I think you'll have the best chances of achieving your goals if you're saving seeds from pod with the preferred size, shape, color, flavor, heat, et cetera.
I've found that my late season pods are sometimes uglier, specifically Bonnets, which tends to get the droopy, no-waistline effect as the temp and humidity drops. I know it's environmental factors, but I still made a point of saving from August's pods this year. . . because I believe (perhaps incorrectly) that I'll be a l'il more likely to get perfect Phenos in 2019 if I'm selecting seeds from perfect pheno pods in 2018.
In short, what Isaac C and countless other folks have said and have been saying on this forum for years...