If the displacement of the ashes was important, I'm sure that High Priestess Maxine Dietrich would have said something about it. When you burn the paper with your blood on it, your blood is dispersed into the air. That's all you really need to worry about. It's your signature and what you said. It's a secret between you and Satan. This is a very personal and important ritual. It's OK that you question everything like that though. Everybody that's new does the same thing. Trust the High Priest/ess and what they say. It will save you untold anxiety.