Not talking about tax forms, I’m talking about applying for a loan.
As someone who works in the mortgage industry as a profession: lenders generally do not care about what an applicant puts down as the "Owner Estimated Value" of their listed property. The only time any additional due diligence is done is when the property in question is needed for some form of collateral or qualifying asset (such as validating estimated net proceeds from a pending sale), in which case the lender utilizes their own tools and processes to validate whether the OEV is supported (and if it isn't, they'll just update the application with what the actual lender's value estimate is for qualifying purposes).