He doesn't have to. There are lots of instances of interpretation or precedent in the way the company does business that are not specifically stated in the CBA. This is how the company has always processed training in at least the last 10 years or so. Training dates are a function of BOTH the seat you are coming from, and the seat you are going to. Generally, things happen in seniority order, but there are always staffing issues with regard to instructors, and different domiciles/relocation issues and like kronan said, bidding to relieve vs. being excessed, that throw a wrench into the works. These things potentially affect passover pay, but the company builds the training letter. Not sure about exactly how passover is computed.