I think folks are confusing terms here.
Anyone can be a PowerSeller as long as their feedback is in good standing and they meet the requirements of 100 transactions in 12 months and 2 or 3k in sales. (I forget which.) To be a Top Rated seller requires some hoop jumping - 1 day S&H, 30 day returns. Just being a PowerSeller doesn’t qualify for their minimal discount, you need to be Top Rated as well.
Also, if you as a seller are paying $17 out of pocket for shipping your product, you’re doing it wrong. Shipping should be paid by the buyer or baked into your sale price if you offer free shipping so you’re making the margin you need to.