BNSF's Crew Management System has apparently been improperly programmed to track eligibility for Personal Leave Days based on an employee's last compensated service rather than the assignment owned. The result was that employees assigned in road service qualifying for Personal Leave days who worked emergency on a yard or road assignment that did not qualify for Personal Leave days would have their Personal Leave day request denied. BNSF now advises that reprogramming should be completed this week and the new program will then be tested. Barring any problems in the testing stage, permanent implementation of the new program should be accomplished by the end of September. Personal Leave day eligibility will then be determined on the basis of the assignment owned rather than last service performed.