Figure morphs don't transfer well to clothing unless you have those particular morphs already embedded or a method to export morphs from figure to clothing. If you own one of the most current Poser versions, you can transfer figure morphs to clothing within the app. The only issue which can impede faithful fitting is how well the mesh is constructed for clothing.

On a technical note, you should pose your figure first before dressing, there is a better chance that the clothing will conform properly with little adjustment.