I don't understand why everyone wouldn't choose the "Performance" Plan (4%+) over the "Classic" Plan (flat 4%) in the Amazon Payment Structure because it seems to me that you are guaranteed 4% with either one, but I thought since Amazon offers a choice and I'm unexperienced, I may be missing the catch.
Yes, you are guaranteed 4%, but with the Performance Plan you can earn more if you have more sales. Consumer Electronics will be 4% no matter which plan you select or the items shipped in the month. If you have 6 General Products items or less in a month it doesn't make any difference what plan you are on, you will get 4%. But if you refer 7 or more shipped items in a month then your commission is going to be higher, so that is why a person would select the Performance Plan.
If, for example, there are 115 items shipped and you are on the Performance Plan, your commission is 7% instead of 4%. Amazon calls it your referral rate. It can go up to 8.5% on the Performance Plan while you would be stuck at 4% with the Classic Fee Structure.