If a replacement is feasible based on TEC, will this pre-emption be time-neutral?
Similar to the rules for assigning a mechanic to a machine, the higher ranked mechanics
within a category should have a greater utilisation than the lower ranked mechanics, in
order to justify their higher cost. Yet, in order to maximise machine coverage, the amount
of time that will be saved if the replacement occurs must exceed 0, as expressed by
Equation (2). (There is an implied assumption in Equation (2) that there is non-Markovian
memory in the repair time, which is left as an area of future study.)