Battle points not gained correctly for heros/villains in Starfighter assault

Battle Points (BP) and Experience Points (XP) are not always equal, depending on whether you are selecting in-era heroes vs. out-of-era heroes.  I can never remember which way it goes though.  I believe the in-era heroes are cheaper in terms of BP cost, and therefore gain BP at a lower rate, although the XP you get towards leveling is the same, regardless of era.