Yes - and the recipe acknowledges this because it says mix the 'remaining' dry ingredients after adding half the sugar. So they know that sugar is a dry ingredient. This is a tricky one. Its not quite detailed enough. But when I read it through I understood it. It would have been more accurate to say (see my bold):
1. Melt some butter in a cake pan
2. Pour 1/2 cup sugar over melted butter
3. Mix the other dry ingredients (flour, etc)
4. Cream butter and remaining sugar
They didn't say "remaining," that was my paraphrasing. The direct quote is "Whisk together dry ingredients. Set aside."
That's why, say what you want otherwise, I appreciate the fastidious meticulousness of America's Test Kitchen/Cook's Country. They can sometimes go a bit too far, but reading one of their recipes, it's obvious somebody sat down and put some thought into it, instead of just dashing it off and figuring, "they'll know what I mean."
Others may not agree, but I strongly believe that recipes should be direct and accurate, with as little room as possible for guesswork. A person shouldn't have to study a recipe, or stop and think, "ok...let's go over where these ingredients go...," if a recipe is a puzzle, it's defeating the purpose, IMO. This one was particularly pisserly (I just made that up, I think), because it's a fairly subtle mistake. I've read through this probably five times in as many days, but it's one that doesn't reveal itself until it's too late.
In my notes next to this step, I've added, "...except the sugar, you dumbazzes!"