Your quote sounds like one of the tweaks in the AU Mod.
This particular change is a result of the first of the AU Mod's two goals (which sometimes compete with each other), whic are: (1) the strengthen the AI; and (2) to introduce more strategic choice for the human. The combination of the changes means that the overall effects and severity of corruption and waste are unchanged, but nonetheless does produce other effects. For one thing, it increases the number of cities needed before you can build the Forbidden Palace. For another, it decreases the cost of the Palace in comparison to the cost in the same circumstances under standard rules.
Both changes are designed to strengthen the AI's play and slightly weaken the human's play. Since the AI almost always builds its FP really close to its Palace and then never relocates the Palace, the AI never gets the more advantageous implementation of the Palace-FP locations that human players employ (i.e., the AI doesn't get two true "cores" of productivity.) The increased number of cities required before the FP becomes available makes it harder for the human to quickly set up two functioning cores. Finally, the reduction in the cost of the Palace weakens the Palace pre-build tactic that many players use to secure great wonders without a great leader.
Catt
EDIT: You posted the same query in the Strat Forum and alexman responded there with an additional intent of the change. In the interests of completeness, I'll add alexman's note that the increased OCN aslo encourages the AI to grow larger empires. The AI will generally stop expanding once it has reached the OCN - thereafter it starts razing captured cities. With an increased OCN, the hope is that the AI will capture more cities, increase its empire, and possibly even achieve a domination victory (which it basically never does in standard play).
