Some time ago I asked a question under I think the topic Diabolic Hybrid or something and replies told me that you can put one character's head onto another's body, but the limitations will still be there.

New question:
If I like for example a model that I bought for A3, is it possible to withdraw the morph dial count values and re-use the dial count values in A4 to have the same face, but in the newer version?

Some models you just don't want to lose! Or is there perhaps a program available that can do that, or a tutorial?

Doubtful, is the short answer.  Since the models are different meshes and therefore the vertices are in different places, even if you could extract the morphs from one and stick 'em in the other you'd get all kinds of weirdness. 

If the differences between V3 and V4 are anything to go by, the morphs are completely incompatible to all extents and purposes.

It may be easier and more productive to have both models side by side in the workspace and try to approximate the A3 version by dial spinning the A4 features.

Sam's got it right, you can't do that.

All you can do is try to get a simular look using the other figures own morphs or create a new hybrid  of combined figures and you already know the limitations. The only real limitation would be the UV mapping of the two figures and if you have the time you could remap the UV's of the neck and head to match the body UV's or the other way Mape the body to the Heads figure UV's.

You can do that in UV Mapper. Not sure if you need pro version or if the classic / free version will do it. I only have the pro version. Really it's just a matter of importing the one map in the texture map layer and then opening the UV's of the other figure and moving the UV verts to match the map.