You've never working in software development have you? Most of the time, the customer doesn't even know what they actually need (or want)...

Personally, I don't think that we need fancy sliding bars with pretty colours... the 4 options they currently have (Priority, Normal, Economic and Low-Prio) combined with a 5th "Manual" option (probably best to be hidden by default and only enabled via advanced settings) would be my idea of the a "good" solution.

It would allow those who want to "Keep it simple" to do that... and for those that want more control to be able to specify their own level of fee/risk. Everybody wins.