What I'm saying is that the land vs structure split is probably not being properly assessed because it's not relevant since taxes are based on the total assessment and unless you have a special tax status for your land the split doesn't matter except in your head where you think you're being treated unfairly.

I can't assess if you are being treated unfairly however because what matters is the comparative total assessment value as a % of market value for your entire property compared to those of your neighbors.

It is extremely common for people to challenge their assessments and they have varying levels of success depending on the town or city (which you've also left out). Most towns have only 1 assessor, sometimes even part time.