Perhaps I missed nuance of the question, but yes, I was referring specifically to the tee's SIF.

In CAESAR's eyes, the stresses are associated with points along the pipe's centerline, and generally not stresses on arbitrary points around the piping's circumference.

So in the case of an elbow, the code provides SIFs to emulate stress at the highest stress point between the intrados and extrados, between inlet and outlet. CAESAR dutifully estimates this highest stress point, too, and reports such.

The same can be said of custom fabricated tees. Based on the B31.3 algorithm, it estimates the highest stress point for the configuration at hand through the SIF and labels the entire connection as either passing or failing.

This SIF can be estimated through FEA, as well in order to outperform the code, but we can all agree that if you want to know stress levels at specific points, we have to construct that geometry somehow and calculate it.

But if you can back out the math do it on pencil and paper, I'll be impressed.