“Doubt As To Liability” is a term used by the IRS which indicates that you probably do not owe additional taxes
If your tax advisor can persuade the IRS of this, your case returns to the audit stage for review. Yet a return review rarely happens. If you are confident in your case, you can fill out and file an Offer in Compromise form (Form 656) with the IRS.
You generally do not need to file any financial declarations when your tax return is under “Doubt as to liability.” Your tax advisor will assist you in making this determination.