"If you export from Poser the correct way, the object file will be the exact same as the one you can find in the geometry folder."

Then please tell me the correct way!

When I export V4 from P6 I get an obj with 69759 vertices whereas blMilWom_v4.obj has 67619, which is 2140 less. Choosing weld before export doesn't change the vertex count. It welds the mesh and leaves 2040 free vertices.

"Only if you chose "weld" from the export dialog the vertex order will be changed.
Of course an unwelded object will split when you try to smooth it in ZBrush or similar, but that's not Poser's fault."

Given that the original mesh is not split into body parts and has no issues in ZBrush, you seem to have just contradicted your statement I quoted first.

"So, hmm, I honestly don't see where the problem is ?"

Some of us like to develop morphs outside of Poser and life is much easier working on a mesh that hasn't been carved up into pieces. The problem isn't with Poser rigging, the problem is Posers inability to export an obj with the same vertex count/order as the inported object if the obj has groups like V4.

Like I said, Poser and DS are the only two 3D apps I know of that won't let you save off a geometry with the same vertex order/count as it had on import. This does make it more challenging to develop full body morphs in other applications. If you do everything from within either application, then I agree that it is not an issue.