Carbonation ratios

I have been kegging my beer for about two years now. I found the carbonation tool in BS and saw that you can adjust the ratio of CO2 in the beer. BS recommends 2.4. Now i'm curious. Does this mean certain styles would be better with different ratios? If so is there a calculation based on SG or something in order to figure it out? Or  is a CO2 style guide somewhere? Or is it just a matter of preference in which case I prefer to keep it sinple and use the same ratio all the way around. Although I'm intrigued now if this will give me more options or another way to experiment.

There are several websites that list desired carbonation levels for different styles.  Not sure if Beersmith has default CO2 values for different style or not, but I know you can adjust it.  Hope this helps.

Thanks for the info.