This is a bug report -- I noticed that sorting does not work correctly when you add in HTML to the end of the cells. I wouldn't think this would impact cells where they start with numerical values, but apparently it does.
Example where sorting works: http://jsfiddle.net/phb9Lms6/
Example where sorting does NOT work: http://jsfiddle.net/phb9Lms6/1/
Click on the "Totals" column to see what I mean. How do I fix this?