Unallowable Costs

I work for a small startup company. We are bidding on a small contract (<$750k) on a FFP basis. I am trying to calculate compliant labor rates for our bid.

We have a substantial "unallowable" cost (interest owed to the person funding the company). While this expense is not included in my overhead or G&A pool, does it need to be included in my overhead or G&A base?