The rules of the agreement for eliminating dual coverage described in RS 02001.560 through RS 02001.570 cover the majority of situations where the United States and Portugal would both cover and tax a worker in the absence of an agreement. However, sometimes the application of the normal agreement rules would yield anomalous or inequitable results. For this reason, the agreement includes a provision that permits the authorities in both countries to grant exceptions to the normal coverage rules of the agreement if both sides agree.

The intent of the exception provision is not to provide workers or employers with the freedom to elect coverage in conflict with normal agreement rules. The purpose of the special exception provision is to allow a worker to continue coverage in the country where the individual normally works and has coverage, in order to ensure that the worker will meet eligibility requirements for retirement or disability benefits.

An employee, employer or self-employed person may request a special exception to the normal coverage rules of the agreement. Both countries must agree to the special exception and agree on the country of coverage. If either country does not agree with a proposed exception, the applicable coverage rule of the agreement determines the worker's coverage.