Unless otherwise specified the regulations and the bonding rates established for any crop year shall continue in effect with respect to all free dates for which control obligations have not been previously met, until regulations and bonding rates are established for the new crop year. Thereupon the withholding obligations for all free dates handled or certified for handling or for further processing during such crop year shall be adjusted to the newly established percentages and a similar adjustment shall be made in any bond or bonds already given for that crop year.