LAW OF THE LAND

I have a property which is subject to a TIF district Design Overlay Ordinance. I want to create a parking lot which is a “permitted use” in the current base zoning. They say that I have to comply with their design guildlines which require an tax increment of $500,000. the site is just shy of an acre and I need the additional parking for a neighboring development. the land is worth $120,000 – can they really require me to create a $500,000 parking lot? Has there been any case law regarding this “newer” control mechanism?

thanks
greg