Why would you want to return a different set of data?  This type of output could not bind to external applications like SSRS/SSIS because the system would not be able...

In order for those functions to get the correct value - there must be an object_id and db_id value.  For those rows - those values are NULL because the code...

Just curious - but is it possible the PAGE compression on the index is contributing to this issue?

You cannot reference the 'transaction count' prior to determining that count so it isn't really clear what you are trying to accomplish.  Plus the fact that it is very hard...

Is the sub report in a cell in the tablix?

Why do you need (or want) to switch to using the local account?  That is not a recommended configuration and would not provide any features/functionality over your current configuration.