I wouldn't really say depends on the price of the trade; like for example, you give 4k sellables for a superfart (just an example) and because it depends on the value of the trade the fee would be over 12k gralats which 1. Would be expensive and 2. The person who recieves the sellables would barely get a profit from it.

If that's how I'm understanding it from people saying make the fee about the value of the trade, unless I read that all wrong.