You do know the case isn't about Trump's taxes, right?You do know that it's the government which assesses the tax value of your property for taxation purposes and not the property owner, yes? And you know that the assessed value of any particular property is rarely the market value of that property, yes?
So, Trump's valuation of his property has no effect on the taxes he pays on it. Nor does any challenge to his tax base based on his valuation because the tax assessor will value the property based on established criteria and not on any property owners claims of value.