No, you guys are moving off course here on this one.

Let's start at Chapter 3.
3.1 - The code allows me to do prequalified procedures, but they have to be backed by a written document
3.9 - Here are my fillet weld LIMITATIONS or PARAMETERS. There's not much here dealing with nontubular or non skewed T-joints. It just tells me that I have to "watch it" or be aware of a few limitations on lap joints. That's it, those are your limitations on nontubular fillet welds. Everything else is within prequalified limits.

Table 3.7 provides me my maximum single pass weld size for a prequalified procedures
Table 5.8 gives me my minimum fillet weld sizes (this is a requirement for both prequalified and qualified procedures)

So, where is the illustration for a prequalified joint detail for a plain 90° T-Joint fillet weld in Chapter 3. There is none. Not because its not prequalified but rather there is no need. The code has illustrations for CJP, PJP, skewed, and TYKs because they are fairly complex geometries which are difficult to codify with just language. There's no need to illustrate a prequalified T-joint for a fillet weld.

Why does the code have a section in Chapter 4 for fillet welds? Well, you might be using an unlisted steel or a nonprequalified electrode or nonprequalified welding process, so in those cases you would need to follow the fillet qualification tests in Chapter 4.