Reduced tax burden on under-construction homes requires builders to pass GST input credit benefits; charging higher installments may be profiteering. Under GST, full Input Tax Credit replaces earlier embedded indirect taxes on construction inputs so those embedded taxes should not form part of the price of under-construction flats; builders must pass the benefit of the lower tax burden to buyers by reducing prices or instalments, and charging higher tax-inclusive amounts for payments after GST may constitute profiteering under section 171.