New Brevoort Formspring

Hello Tom, as an aspiring letterer, I have been wondering... Is there any particular reason by titles such as the current Moon Knight and Ms. Marvel have been using lowercase text for dialog while main titles such as the Avengers is all uppercase text? I understand that lowercase it's the standard in the Ultimate line, but what about the default Marvel title? Is it a decision made by the creative team or letterer in charge, the editorial, or perhaps both? Thank you for your answer.