Adding a New OU within R12 - Replicate Seed Data?

I'm about to add more operating units to my R12 (12.0.6) test instance for use just with the Payables module.  I would like to add these new OUs to an existing HR Security Group so that some existing responsibilities get access to the new OUs.

In R12, do I still need to run the Replicate Seed Data concurrent request from System Administrator?

If YES, can any answer the reason why if known?  What errors would I get if I do not run Replicate Seed Data?

Thanks,

Eric