As I'm reading through the OAUG survey (available here) one thing really strikes me. If you look at Figure 30, only 24% of respondents are on E-Business Suite R12.1. Of those that remain, 74% indicated that they are on a version of E-Business Suite that no longer covered under Premier Support.
Remember that, for Extended Support, you will need to achieve "minimum baseline" code levels too!
More information on Oracle's Support windows in this post.