Must tilt cards placed in Section Boxes

Cards placed in the add-on Section Boxes cannot be stored upright. You must tilt them. Or you could take scissors and cut a bit out from the top or bottom of the divider cards (I did this with Prototype 2 card dividers, but I sure would not want to do it with my final game). Here is the photo that illustrates what I am talking about:

Here was the question:

Here is the official response from AR-Jordan about needing to tilt the cards:

UPDATE:

Both the cards and the dividers fit in the default Section boxes with their covers on.