Complex sentence: Usually first class petty officers and chief petty officers with less than 12 years of service are selected for the LDO program, while chiefs with 10 + or more years of service, senior and master chiefs usually are selected in the CWO program.
Split into simpler sentences: Usually first class petty officers and chief petty officers with less than 12 years of service are selected for the LDO program. While chiefs with 10 + or more years of service, senior and master chiefs usually are selected in the CWO program.