What I did was:
Open Daz 4.21, load model to Zbrush, checking the "current resolution" box.
Sculpting in Zbrush
Exporting to .obj
Open Daz 4.6, loading Morph Loader Pro on the model & selecting the .obj, Morph Subdivision set to yes, Build resolution set to 2 (that is the original SubD level of the model in Daz 4.21) and then loading in the morph.
I only sculpted a single line.