myahn, I think you are on the right track, however, the issue is with the investors. You need to work something out with them, maybe even their compliance person.
If it helps, we are in the same situation with investors still holding to that idea of final documents that are totally accurate. They are going to have to live through a few scenarios such as yours to see that they may need to start accepting the valid TIL even if the numbers are off but within tolerance.
_________________________
NOLA is my Beach!