Yeah, that's the intent of the "Dice Etiquette" section. Call the complete action, then roll. Certain specific game mechanics will let you add to the dice roll after it's rolled, and that's fine (and I forgot that Bardic Inspiration is one of them...we don't have a bard, so I tend to forget about them).
But really the point here is to keep the game moving forward. I don't want the players trying to figure out what number they need to meet and then spending 5-10 minutes trying to find ways to add dice to every roll that doesn't meet it. I would rather keep everyone's minds in the story and away from the numbers.