A. elapsed time since the target start date or completion date of previous work generated by PM  
B. difference between completion date of previous work and system date is equal to Lead Time  
C. elapsed time since the target start date or completion date of the latest work orders for the asset
D. metered equipment usage since the target start date or completion date of previous work generated by PM
E. metered equipment usage since the target start date or completion date of the latest work order for the asset