–calc

lotVal + superstructureVal == assessment ~= mktVal

assessment * taxRate == taxPayable

Some NJ towns will provide a breakdown of lotVal and superstructureVal but with or without the breakdown, you can’t do much about lotVal. You can only dispute the total assessment.

Unconfirmed hearsay — If you subdivide a floor to create more rooms, the tax department may increase the superstructureVal. I was told the rationale is that mktVal is now higher.