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.
Equitable remedies were and still are about what is fair and right. A legal remedy, for example, would be damages for a breach of contract. Under the law, a person who is party to a contract can recover damages if the other person breaches.