Sedo will tell you they already offer a 10% commission, but good luck ever getting it.
Yup. In order to have the 10% commission applied at Sedo I believe you need to:
1. Be using Sedo's landers/nameservers (ns1.sedparking.com / ns2.sedoparking.com);
2. The domain must have sold via a BIN on their marketplace; AND
3. The lead must not have come from one of their MLS partners.
So even if you commit to following #1 and #2, the third requirement often ruins it where you will be asked to pay 20% instead of 10% because the lead came from their MLS network. I think that "problem" is partly because their MLS network is actually pretty good. I say that because I still get offers via Sedo even though I don't use any of their nameservers.