Unless otherwise provided for by this Regulation, the competent institution of a Member State whose legislation makes:
—
the acquisition, retention, duration or recovery of the right to benefits,
—
the coverage by legislation,
or
—
the access to or the exemption from compulsory, optional continued or voluntary insurance,
conditional upon the completion of periods of insurance, employment, self-employment or residence shall, to the extent necessary, take into account periods of insurance, employment, self-employment or residence completed under the legislation of any other Member State as though they were periods completed under the legislation which it applies.