Perhaps through the course of your 30 minutes system practical availability you could take snapshots of the Administration overview, to see if usage grows abnormally until your system is no longer responsive?
I would be interested if you have seen this thread regarding "negative CPU index" and whether you also experience this error and significant growth of trace files, viewable via the Diagnosis Files tab, in your Cloudshare instance:
http://scn.sap.com/thread/3409932
I had hoped we would have had more SAP support and communication - disappointing and disheartening. It remains to be seen whether this issue will become more commonplace as the upgrade process to SPS6 rev60 has recently been updated.