Uhh... what's the "intended rate"? As far as I can remember, it was nearly impossible not to out-level content and contacts even at regular XP. I think it's only possible to stay within that range (especially at low levels) is by turning of XP (before you out level content) until your done with that content.
Well, I'm assuming Cryptic didn't intend for you to constantly outlevel contacts and storylines. ;) I do remember running into that issue with characters that teamed a lot while leveling, but not so much with more solo characters. Granted, 2004 was a long time ago, so I could be misremembering. In any case, the current XP boosts make things a lot worse in that regard.