The Administrator may at any time reduce an individual manufacturing quota for a chemical that he has previously fixed to prevent the aggregate of the individual manufacturing quotas and import quotas outstanding or to be granted from exceeding the assessment of annual needs that has been established for that chemical pursuant to Sec. 1315.11, as adjusted pursuant to Sec. 1315.13. If a quota assigned to a new manufacturer pursuant to Sec. 1315.23(b), or if a quota assigned to any manufacturer is increased pursuant to Sec. 1315.24(c), or if an import quota issued to an importer pursuant to Sec. 1315.34, causes the total quantity of a chemical to be manufactured and imported during the year to exceed the assessment of annual needs that has been established for that chemical pursuant to Sec. 1315.11, as adjusted pursuant to Sec. 1315.13, the Administrator may proportionately reduce the individual manufacturing quotas and import quotas of all other registrants to keep the assessment of annual needs within the limits originally established, or, alternatively, the Administrator may reduce the individual manufacturing quota of any registrant whose quota is suspended pursuant to Sec. 1315.24(b) or Sec. Sec. 1301.36, 1309.43, 1309.44, or 1309.45 of this chapter or is abandoned pursuant to Sec. 1315.27.