This article examines systemic issues arising from the calculation of the level of retaliation against WTO-inconsistent anti-dumping/countervailing duty (AD/CVD) ‘measures’ by focusing primarily on two Article 22.6 arbitration cases, i.e., US – Washing Machines (Article 22.6) and US – Anti-Dumping Methodologies (Article 22.6). The two cases show that trade remedy disputes make the choice of the ‘reasonable’ counterfactual difficult, and require careful consideration in analysing the reference period for the counterfactual scenario and the calculation of nullification or impairment, given the unique circumstances in which the aggrieved country is confronted by WTOinconsistent AD/CVD measures. The article also examines that the Armington-based partial equilibrium model employed in both arbitrations is a useful tool for calibrating the effect of a straightforward reduction in AD/CVD tariffs, but it does not elicit the ‘equivalent’ level of nullification or impairment (NOI) because of the assumptions and data used.