Perforated Soffit Installed at an Angle

I want to get opinions about installing perforated soffit at an angle or vertically. I’ve seen this a couple of times and when I was a construction manager we were told not to install this material at an angle or vertically. In other words perforated soffit should only be installed horizontally. Kinda makes sense, especially because of the chance of water intrusion during wind driven rain events. But I looked up the installation instructions and they don’t say you can’t install it on an angle or vertical, but it also only shows installation instructions for installing the material horizontally. Any one got comment on this one?

Why would a manufacturer illustrate how not to install the product? If they show only one way it is because that and only that is the approved and warranted method of installation for their product…