I agree with oraleDK on this one.
The thing is (and I might be wrong about it), that if Klutch makes a transfer, he removes the A/B Meebles from the game and spawns Gamma Meebles in. Setting a fixed exchange rate here makes sense. You don't want the new economy to be overflowed with money right away.
On the other hand, if players do the exchanges, they just move around money. Player A gets A/B money, gives G money and player B gets G money, gives A/B money. Nothing has been removed nor spawned in. It's fine to do any rate and shouldn't be discouraged.
Now the problem with a NPC doing the transfers at a certain rate is, that it would not be relevant really quick as the rate will slowly go down. You can see that already happening in game, where players are doing a 1:40 exchanges instead of the 1:50 Klutch was originally doing.
