Arkansas does not allow local jurisdictions like cities or counties to collect a local sales tax. The Arkansas state sales tax of 6.5% is applicable statewide. You can view the sales tax rates for various cities in Arkansas here.
Equitable adjustment is a term of art that includes an adjustment to fee, and the target. minimum, and maximum fees should not be increased in this case for what I hope are obvious reasons. The adjustment should be limited to the effect of the new wage determination on wages and fringes.
Most simply explained, a constructive trust is an equitable remedy imposed to prevent unjust enrichment (see Simonds v Simonds, 45 NY2d 233, 242 [1978]; Sharp v Kosmalski, 40 NY2d 119 [1976]).