Both CPUs have the same front-side bus frequency... that is defined by the hardware of the motherboard... the only way you can have 2 cpus on a BP6 operating at different clockspeeds to each other is to have CPUs with a different multiplier... ie a 400 in one socket and a 466 in the other.
I think you will find your software has a glitch... also I think you will find that something is wrong with your BP6fsb if it is claiming to offer independent adjustment of each cpu... good luck