"The difference is 82 from total vApps to what the VC is reporting so does this mean 82 VM guest are lost?"
just to add to what cfor has listed:
3. Does anyone have direct access to your vCenter? In our environments we had developers who didn't know any better creating VMs directly in vCenter, which the vCD database will not know about. You should easily be able to determine this by just looking at the VM name in vCenter. If the VM has a long UUID after the name it is owned by vCloud, if not it was created directly in vCenter.
4. it's possible that there could be some expired vApps as well that you do not see