[smeej]

Most of my experience is in customer-facing roles, and I would argue that reading a customer email chain where they try to describe what is happening, sometimes with pictures, requires level 4 understanding.

You often end up with multiple documents (several emails, pictures, logs). There's often competing information (customers are speculating about what's wrong, but they likely include lots of other information because they don't actually know). And you definitely need background knowledge about the product.

Add in translating that into a bug report for the engineering team? A successful high-level customer support agent needs level 5 reading ability.

But my experience asking questions of my teammates in the company Slack channels tells me very few of them are even actually at level 3.