I'm not sure why the round-trip formatter is used in the C# example (https://msdn.microsoft.com/en-us/library/dwhawy9k(v=vs.110).aspx#RFormatString https://msdn

I'm not sure why the round-trip formatter is used in the C# example (https://msdn.microsoft.com/en-us/library/dwhawy9k(v=vs.110).aspx#RFormatString https://msdn.microsoft.com/en-us/library/dwhawy9k(v=vs.110)....). If you omit it then you get the hoped-for result of 0.3.