I've implemented the final results into StatLogicLib r82109, this is RatingBuster's core, where all major math calculations are done.
* baseDodge = StatLogic:
GetBaseDodge([class]) added new values for wotlk
* dodgePerAgi = StatLogic:
GetDodgePerAgi() now implements the formula derived in post
#277 for wotlk
* modDodgeBeforeDR, drFreeDodge = StatLogic:
GetDodgeChanceBeforeDR()
Calculates your current Dodge%(modDodgeBeforeDR + drFreeDodge) before diminishing returns.
* modParryBeforeDR, drFreeParry = StatLogic:
GetParryChanceBeforeDR()
Calculates your current Parry%(modParryBeforeDR + drFreeParry) before diminishing returns.
* avoidanceAfterDR = StatLogic:
GetAvoidanceAfterDR(avoidanceType, avoidanceBeforeDR[, class])
Calculates the avoidance you get after diminishing returns.
* gainAfterDR = StatLogic:
GetAvoidanceGainAfterDR(gainBeforeDR)
Calculates the avoidance gain after diminishing returns for gainBeforeDR with player's current stats.
As for RatingBuster itself, r82110 has DR support for Dodge% and Parry% differance values in StatSummary, and an option to turn DR calculations off, only works in wow 3.0.1 or above.