If it's +/-, it isn't the same... I'm using the Heiland SplitGrade, so it will do 1/10 increments (although I can't really see a difference with a 1/10 change. I can at 2/10).
But, I do agree there are a number of ways to get where you want to go.
Yes it should be noted a colour or VC head is infinitely variable between grades so my 1/4-1/8 grade margin applies only to the use of external filters.