Sync apps and downloads across multiple iOS devices instantly, using the same iTunes account.

My wife and I share one iTunes account across two iPads. When one of us used to download an app, it would instantly appear across both devices (like in the commercial). That has recently stopped working (if I download an app, it will only be on my iPad). It appears to me as though I have my iTunes settings correct and authorized automatic downloads "on" in settings. I also have two iPhones and want this to sync across all four devices. What am I missing here? Please help!