setFormat() call with maxDecimal property = -1 does not work as expected

Hello, when I have a grid with a global format with maxDecimal of 2, and I then use setFormat to set an individual column format to have a maxDecimal value of -1, the decimal places in the data do not update properly to show the underlying data. See example here: http://jsfiddle.net/eo1zh0qv/
 
Here's an example of behavior working as expected when using a value other than -1 : http://jsfiddle.net/y1vjrLd9/
 
Thanks for your help!