How do I see who's marking my DSR down on postage?

[kustomizer99]

One or two buyers don't seem to understand the true cost of postage. Especially now that the cost of insurance is not indicated on packages. Apparently I'm able to see who's been marking down my DSR on postage -- does anyone know how? Like most things on eBay it's completely unintuitive.

[*tippy*toes*]

One of my buyers wasn't happy with my $8 postage for 3 items combined. He left me positive feedback, but said postage was expensive. I haven't checked what stars he left yet, but my postage cost star has taken a beating, so I'm guessing he gave me a 1. I've only got about 15 star ratings on that account so it doesn't take much to ding those stars. I did have all 5's before that. Now my postage star is around 4.7. The rest are still 5.