I am also a top rated powerseller on Feebay (love that name) and yes I lose in the area of 18-20% after all the fees including paypal. I have tried Itsy, and Amazon but they are not even close to the traffic levels I get. Sad to say that just recently I had to add a handling charge on my items to recoup some of the fees. I've been with them since the beginning, which is like 14 years, and yes the fees are off the wall, but if I'm making 100-5000% profit on an item, I guess I'll just have to deal with it. People are creatures of habit, and even though fees keep rising, this does not hurt the buyers, and it's the buyers that us sellers need. The buyers have no reason to leave Feebay.
Hope this helps.
John