Can't please them all

I'm a little bothered now by the change Ebay made to the feedback system a while back. It seems that sellers cannot leave anything other than a positive feedback, no matter what. The buyers, however, can leave positive, neutral, or negative, and then there's also the star ratings. To Ebay, you need to have 5 stars, to remain a powerseller, you have to have a certain amount, or they remove you from the Powerseller program. So, why is it that lately I'm getting great feedback, but not so great stars? I had all 4.99, now it keeps going down. Is it so wrong of me to wonder why someone didn't think I charged a fair shipping amount, when they only paid .10 over the actual cost? That won't even cover the ink I used to print their postage. And don't get me started on shipping time. People seem to be confused on this one, they think I am the post office I guess. I ship when I get your payment, it goes out the following day, as long as there is mail that day. If it takes longer, it's because you took longer to pay! I'm hoping Ebay changes this soon, and for the better.