In Gen 4, Simple is a passive ability that doubles the effect that a given stat increase or decrease level has on stats. For example, using Calm Mind would still provide a +1 boost, but the Simple ability doubles the amount by which a +1 boost raises stats. Using Baton Pass or Psych Up would pass the +1 stat level, not the ×2 stat increase resulting from Simple. This also works the other way; a Simple Pokémon receiving a +1 boost from Baton Pass or Psych Up would also have its stats doubled.
In Gen 5, however, Simple is an active ability that triggers any time a stat is raised or lowered, doubling the stat levels themselves. In this case, using Calm Mind would actually result in a +2 boost, which is retained through Baton Pass or Psych Up. However, this also means that a Simple Pokémon receiving a +1 boost from Baton Pass or Psych Up will not receive double the boosts like it would in Gen 4.
So ElSilverWind was correct TC, a Swoobat using Calm Mind will in fact receive a +2 boost. --- Pokemon Black FC: 1850-6413-0450