Have you seen supermarkets that have the price/kilo in the label, even if the product is 245grammars?
People try all sort of things, to get a good trade.
An column with the ratio, would be very practical to keep silly offers from happening.
For example 500 stone for 50gc (10/1) - that would be easy ok.
1330 for 20 ( 66.5/1 ).
etc.
This would be very usefull against GC, but even in other goods, and it would help players spot the good deal very fast, and keep trades being more fair. Even the noobest player would spot the scam right away. He would be able to SORT BY that column for example.
It would make trading a better place to live!