This may be worth additional conversation with me offline or with a Sales Engineer, but if I understand your question correctly I think you are using thinking about FoE and APE incorrectly.
Have you seen these?
- http://thwack.solarwinds.com/community/solarwinds-community/product-blog/blog/2013/04/09/what-is-the-difference-between-high-availability-vs-disaster-recovery
- http://thwack.solarwinds.com/community/solarwinds-community/product-blog/blog/2010/11/08/orion-failover-engine-deployment-options-and-qa#comment-164789