You certainly own enough licenses. Just remember you definately do not want to upgrade if your using vbGallery because I think based on what I am seeing with vb5 that this is probally end of cycle for vbGallery meaning that product is essentially done.
I doubt after all the work of PhotoPost 8 in regards to mobile technology social networking etc that going forward your going to see anymore development in vbGallery since it requires extensive work everytime vBulletin releases anything. Too much work and no money intake. It just has never been a fiscally responsible product.