We look at the expected work effort and elapsed time to complete the two alternatives. The first option has one consolidation and one upgrade project. The second option has two upgrade projects and then a consolidation project, so it is likely to require more work. Using eprentise to consolidate 11i instances or R12 instances is about the same level of effort. It would also take longer if the two upgrades are done one after another instead of in parallel.

There are other considerations. 

• Upgrading to R12 is largely related to keeping up technically with Oracle's releases. The business reasons for an upgrade are usually related to needing the new accounting methods and new module functionality not present in 11i. R12 introduces Ledgers, Ledger Sets, and Subledger Accounting Methods. Setting up and staffing shared service centers is easier.
• Most companies delay the upgrade, since it's a lot of work without a lot of business benefit, and they want to wait until R12 is stable. Also, many of the advantages of R12 are meaningful only if you have a single instance.
• Users test the consolidation transformation on a familiar release. By using eprentise before upgrading, you are able to isolate the impact of consolidation changes without introducing the complexity of a new release, new functionality in new modules or new features in existing modules, and different business processes.
• Consolidating to a single instance has business benefits regardless of the release you're on. We believe (a) a company can estimate the business benefits with a small amount of financial analysis, and (b) the benefits will be significantly more than the combined technical and business benefit of an R12 upgrade on multiple instances.
• In summary, even though R12 is more stable than a year ago, we still suggest consolidate then upgrade as the sequence of choice.