The user set up 3DS Max for centimeters and didn't do any pivot rotation. When exporting with the FBX the results are fine, but with DataSmith it is tiny for the actual geometry.
This issue was reported and tested in 4.20 (4.20E3). It was reproduced in 4.19.2 (0.182)
Results: The imported geometry is tiny compared to the imported DataSmith scene
Expected: The geometry to be the same size as the DataSmith scene
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-64516 in the post.