Used the same process for both applications.
Load Antonia. Zero her. Load the Bottoms.
She comes in both apps in the same pose. Apply Fit To in DS works fine. Apply Conform To in Poser and I get the results above. I even tried setting her pose to the standard T pose before loading the Bottom  with no luck.

Edit -
I have reinstalled the old set (dated 13 March) and they conform without any problem. It is therefore something that was updated between the two releases.

Hope this is an easy fix - I know nothing about clothes creation.

Poser Pro 11, DAZ Studio 4.9