But both ansys and lsdyna are capable of modelling these elements, which makes the statement by NIST a strange one indeed. The models that they used are very limited looking though and do not support their own conclusions. As for time and financial constraints, I agree there, but some of the errors that they made were so basic that there are no excuses. ie 11/12" mistakes, elements missing etc etcThat divergence shows the sensitivity of the models, and the error in insisting that there be one crucial make-or break event that the entire collapse hinges upon.
The models really don't have enough level of detail for such precision. Only the first one comes close, and that's super limited in scope.
Basically I think they were limited by time and budgets.