An operator may conclude that a specific requirement would fundamentally alter the basic nature of the product or service, or would impose a disproportionate burden when assessed against Annex VI criteria. That conclusion must be reasoned, specific, and documented. It is not enough to say accessibility is expensive or difficult.
The assessment should show what requirement is at issue, what design or implementation options were explored, what costs and benefits were considered, and whether partial compliance can reduce burden while still materially improving access. For services involving self service terminals, the directive explicitly expects operators to consider whether a limited number of fully accessible terminals or a limited level of accessibility can avoid a disproportionate burden while still moving toward compliance.