The reference to 03P (CPT Promotable) and 04 (Major) is a reference to a point or time in your career when unique opportunities become available to Chem. Corps officers with technical degrees. After you have completed your time as a Platoon Leader, some staff time, and a company command you will have about 8/9 years in and likely eligible for Major (04) but not yet promoted... you are an 03P (CPT Promotable) at that point. A number of 'jobs' in the Army (Research Labs for example) require specific degrees like Chemical Engineering, Chemistry, Bio Chemistry, Physical Chemistry, Laboratory Science, .... I don't know if Chem Corps is faster to promotions than other branches but with a technical degree in Chem Corps you are eligible for 'jobs' others are not. When I was in, CPT (03) could be achieved at about the four year mark. Major at about the nine year mark.