This deserves some explanation, stating with the fact that what these new options mean is that one can essentially order the same configurations on both models. Previously, the 2.3GHz model came with 8GB of RAM and 256GB of SSD storage, period, for US$2,199. For $2,799, one could get 2.6GHz, 8GB of RAM, and 512GB of SSD storage. You could also opt for a 2.7GHz processor, 16GB of RAM, or 768GB of storage.
Those options are all still available for the $2,799 model, but customers can now also select those same options for the same price on the base model, as shown in the screenshot below. In this way, you can arrive at the exact same high-end configuration even if you start with the base model.
Apple Store Screenshot of Entry-level MacBook Pro with Retina Display Configuration Options
What is specifically new is the ability to keep the low end processor while adding more RAM and/or more storage. Users can also now add iWork apps (Pages, Numbers, Keynote) as pre-install options.