Per clause 39 (Compliance with Laws) from the Pro-Customer Long Form Outsourcing Agreement. What would be the supplier response and the Customer counter-argument for the below clause

39.3 The Supplier shall make any modifications to the Services as reasonably necessary as a result of such changes at no extra cost to the Customer other than where the relevant modification is required to address a change in legislation that is specific to the Customer in which event the effect on cost shall be assessed by the Change Control Procedure.