A labour rate per unit is the result of a cost and an output assumption. Discussing the final rate alone can hide the reason it is high or low.
Use a common time basis
Start with the crew cost over a defined period. Compare it with output over the same period. Hourly cost divided by daily output is not a meaningful unit rate unless the time bases have first been reconciled.
For example, a training crew costing 101 per hour and producing 8 cubic metres per hour has a labour cost of 12.625 per cubic metre before rounding. These are illustrative values for explaining the method.
Separate baseline output from adjustments
If an efficiency factor is used, state what the baseline represents. Explain whether breaks, access constraints or expected delays have already been included. Applying the same reduction twice creates an allowance that may be difficult to recognise in the final rate.
An efficiency percentage should describe a specific assumption, not act as an unexplained correction whenever the result feels optimistic.
Test the work method
Ask what controls the crew's output. A larger crew may not improve production if access, supply or another activity remains the constraint. Additional resources can increase cost while leaving effective output unchanged.
Review the method, sequence and constraints before debating the last decimal place in the unit rate. The calculation should make the judgement visible, not replace it.