A disability (i) as determined under The Atmos Energy Corporation Group Long-Term Disability Plan, as in effect from time to time, or (ii) a determination of total disability for purposes of eligibility for Social Security disability benefits, if such Group Long-Term Disability Plan is not then in existence. If a Participant’s Disability is based on his eligibility for Social Security disability benefits, such Participant shall not be treated as having suffered a Disability unless he shall provide the Plan Administrator, or a committee which may be established pursuant to Section 6.1, with written proof, in a form and within the time determined by the Plan Administrator, or a committee which may be established pursuant to Section 6.1, to be satisfactory, that such Participant is receiving Social Security disability benefits.