This is my opinion, but...
SIF terminology only applies to elbows and single-branch constructs, of which this has two. As such, there is an interaction between the two branches that is not readily interpreted within the piping code or the software. Essentially, the SIFs of the connections could vary greatly based on what is happening at the other ends.
You would have to CNODE-anchor the three connections of this construct, and if the manufacturer of the fitting cannot provide you allowable loadings, you would need to run an FEA on it.