Okay, so I am looking over the CBO letter, and the first thing that strikes me is this disclaimer:

Although CBO completed a preliminary review of legislative language prior to its release, the agency has not thoroughly examined the reconciliation proposal to verify its consistency with the previous draft. This estimate is therefore preliminary, pending a review of the language of the reconciliation proposal, as well as further review and refinement of the budgetary projections.

This suggests that the CBO has been trying to score a moving target, with Democrats making frequent tweaks to whip votes and/or hit deficit targets. So the CBO isn’t sure they’ve scored the final bill — hence they are calling this a “preliminary estimate.”

Congress Daily’s Anna Edney reports that a final CBO score will come out Saturday or Sunday, a most unfortunate bit of imprecision considering the vote on the bill will occur on the latter.