Regular Part-Time and Casual Employees Progression on Wage Grid. Regular part-time and casual employees shall accumulate service for the purpose of progression on the wage grid on the basis of one year for each 1725 hours worked. Notwithstanding the above, employees hired prior to March 31, 1999, will be credited with the service they held for the purpose of progression on the wage grid under their previous Collective Agreement or working conditions, and will thereafter accumulate service in accordance with this Article.