There are two barcharts (one is interactive the other is a png image).
In general you can add more bars by pressing the '+ Col' (add columns)
button. Let me know how this works out for you.
I am not sure I understand the .2 and 20s problem.
Internally it will remember all the precision you use. Only in the
spreadsheet it will display less. If you click on the bars you will
see the real value. Example:
http://www.chartle.net/embed?index=30238
Does that answer your question?