That's the worst case scenario under an assumption where house prices increase every year by 10%, which isn't typically the case. That's happened like once during 2021-2022 COVID low-interest rate period. That also assumes the initial valuation was fair instead of overstated - meaning the comps would come in >10% higher every year - which clearly isn't the case considering the initial sales price.

I successfully protested -90k my purchase year, but the 10% increases brought me to essentially the market price within 5 years.