I did not see any issues with the model. The only thing that is missing is a LOAD LIST command before both the strength and the serviceability checks just to ensure that strength check is done for the combination 7 and serviceability check is done for load combination 6. Modified file is attached.
I am not too familiar with the standards you mentioned and so cannot comment on whether a U Frame analysis is mandatory or not. However my personal take on this is, a properly substantiated 3D analysis is much more accurate than any manual analysis.
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