Paint codes and paint mixing

Hello all,

I am currently restoring a VW camper van which will need a respray. I have chosen what I think is the most beautiful colour around at the moment - Punto New Orleans Blue.

My local Fiat dealer tells me that the colour code is 599 but when I went to my local paint supplier (Hex) , their computer gives this code a different name and on the colour swatch, the shade of blue is much darker and flatter!!!

My questions are: Should the 599 code be followed by a letter A to denote a metallic colour? Can Fiat dealers supply big cans of this paint so that I know that I am getting precisely what I want? Does anybody out there have a 2006-2008 Sporting Punto in New Orleans Blue to confirm the colour code for me?

Any help would be much appreciated. Thanks in advance.