ohhh, I know what's happening there! You don't have to do this manually. I am assuming you have Poser pro 11. Once you have the full body morph dial created, right-click it and a little context-sensitive menu will show up. From the options, click "Match centers to morph". This will open up a new dialog to let you choose which joints you want to be affected. Whatever joint positions you select on this dialog will be controlled by your morph dial. In general, it tends to do a very good job, BUT you may have to adjust the ball-joints like collars and thighs. Depending on your morph. those may need adjusting. Once this is done and your figure is saved to the library, the skeleton will self-adjust whenever you spin your morph dial.
However, if you want to add changes afterwards, you have to do it using the "Dependency Editor", or else the changes will NOT be saved as part of your morph. This is what happens globally in 1-step with the process I have described above, but later adjustments have to be done individually with the dependency editor. And remember to re-save your figure if you made such changes.
For some reason, Poser has an old issue regarding NOT keeping some changes when saving to the library - UNLESS you manually set it to "Show hidden parameters" BEFORE saving anything to the library. Morphs and parameters that were hidden during saving will not be included. I have reported this terrible issue to SMS, but they still claim it's "normal" and doesn't need to be changed. So beware!
If you make DS versions of your morphs, this can be a bit more complicated if you want to do changes to joint positions after saving to the library. There is an extra step you must do, which is to BAKE the current joint before editing the joint and freezing the ERC, or else, DS will create a duplicate of the joint parameter on file. If that happens, next time you load your morph, DS will display that infamous "duplicated formula" error message - which pretty much describes what the problem is. This is kind of ironic, because if DS can detect when a joint parameter is duplicated, it could had avoided it in the first place, by offering an option to replace instead of duplicating. Anyway.... if you want to edit a saved morph with adjusted joint positions, just remember to bake before editing and freezing ERCs in DS.
Hope this helps.