Kinda very interesting and simple.
I think I would use it if ores/enmaters and other usual stuff (wools, hides etc) will be included.
Hate to use calculator in each trade
+ rep for simplisity
Only question: does it work on the top of
EU (like
PE ASS), or in the background (couse atm windowed mode for me isn't possible and I don't now why

)?
and maybe would be usefull to add the column for tt+X items (lol, it would be for the lazyest people)