I understand your frustration redrumloa, but I noticed that you don´t mention the 1-5$ handling fee in your listings. So I imagine that it can be a small surprise for some buyers.
But still, that discont drop is a harsh penalty to receive for a small feedback change. I sympathize with you Red.
Now the buyes should have asked you about that when they received the goods and saw the postage, but I guess most of them bought items where 1-5$ was really small amounts compared to the total and they rather "bit" back through the rating system.
I always communicate with the seller through ebay if I feel something is wrong. But I have seen that it´s not as common place as one would wish.
So my advice to you red is to add the handling fee in the ads, and to future buyers to communicate through ebay with the seller both before the purchase and after the purchase. This way ebay have a record, and both parties stand stronger.
On a side note:
I´ve stopped giving the seller my personal e-mail in the ebay message form. I hate it when I ask the seller an important clarifying question about the terms, and then he/she replies privately through email. For boths sake = Have it documented in the ebay message system.