How Resources are Shared in the SLES 11 Priority Scheduler - comment by desai51

Hi Carrie,
I am trying to understand the pros and cons of Virtual Partitioning (VP), specifically Dynamic Virtual Partitioning.  We have a shared system where two sister companies sharing the cost with a split of 30% and 70%.  We are at 15.10 and have TASM.  I understand the a VP is the top level in the hierarchy under the internal control group 'users'.  I want to understand how VP can help us manage resources better within a multi-tenant system.
We want to be able to assure that Company S, which should have a 30% share is guaranteed atleast 30%.  We don't want to use fixed VP since it would impose a hard limit on each company even when the other company does not have a heavy work load at some point in time.
1. Let's say we have two dynamic VP with a 30:70 split (for company Sm and Bg resp.,).  Assume that Company Bg is using 10% of the system, and Company Sm is using 30% of the system.  My understanding is that in this case Company Sm can exceed the 30% limit and consume more resources because company Bg is not using it's full partition share.  Let's say that with Company Sm running at 30% of the system, it issues a query ends up needing an additional 20% of the sytem, so now company Sm is using 50% of the system cpu.
2. Further, while Company Sm is running this long running high cost query, someone from Company Bg wants to run some expensive queries.  What happens in this case?  If Company Bg's query is a high CPU query (say needs an additional 40% of cpu), then does Company Sm's query immediately get's less access cycles and thus free up resouces above 30% for Company Bg?  Not sure if TASM demotes the Sm query and the effects are immediate (as in a few seconds) or not.
Or does Company Bg have to wait until Company Sm's query is finished before getting CPU cycles to consume ?
Thanks,
Amit