Hi, This is a problem that seems to present itself frequently. I'm using Creo 3 at the moment so if 4 is different I apologise. The issue is that in the analysis where you can see the cog this is a stored state. To make sure that you see the current cog I would always go to the File tab and look at Prepare\model properties\mass properties click on change. To be sure the figures flush through I would do calculate then generate report.
Additionally if you want to see this in the model permanently you can use a CSO with the x,y and z values generated from pro_mp_cogx, pro_mp_cogy and pro_mp_cogz. Type those parameters into the x,y and z values and it creates a relation to the cog.
Hope this helps
