How can I fold down both second and third-row seats so that I have a completely "flattened" cargo floor on my 2021 CX-9 GT? I can get the third row to be completely flat but I can only get the second-row seat-backs to lay on top of their seats. However, they are not completely flat. The manual is confusing in this area as it refers to other sections of the "Book". This manual shows the second-row and third-row seats totally flat as a picture indicates.