According to the remittance from Wells Fargo on WBCMT 2007-C30, credit support on class G is 5.84% which will match Trepp. However, that same c/s level will be different should you consult it on Bloomberg or Intex. Why?
The main culprit are WODRAs. For those of you who have not had the pleasure, WODRAs represent servicer recoveries of advances from principal as opposed to interest cashflow. In the case of C30 as of May 2014, $6.813MM of bonds are supported by $6.807MM of collateral. This $0.06MM principal shortfall can only be recovered if REOs are sold for more than their loan balance, which is usually not the case.
What does Trepp do? They match the trustee remittance, which totals all bond balances inclusive and subordinate to the given bond and divides that by the total bond balance. To Trepp's credit, they also report an ARA-adjusted c/s level which takes into account B-notes (which are usually 100% loss) and appraisal reductions (although surprisingly, not loans declared non-recoverable which have a 95% loss severity on average, last time I looked).
What does Bloomberg do? They total all bond balances inclusive and subordinate and divide by the total collateral (as opposed to bond) balance. Better, but still incorrect since B-notes, appraisal reductions, and non-recoverable loans are considered money-good.
Finally, we consider Intex. Although they do not adjust their c/s levels for B-notes or ARAs, they do back out under-collateralization resulting from WODRAs from collateral balance as their denominator. And they provide forbearance and non-recoverable loan data so that the enterprising investor can figure out what real c/s levels are. All hail Intex!