For me it kind of depends on the recipe. For something like a dark roasted malt that I'm using in a relatively low amount to begin with I may leave the quantity the same, especially if it's there primarily for color. Otherwise, I usually scale by percentage, but then I start rounding up the specialty grains to an even number of ounces because I have OCD like that.
I have CDO. It is similar to OCD except the letters are in the correct order. And I do the same thing you do by rounding ounces out.
Thanks again to everyone for your contribution to my continuing education.