To allow for this loss we can add a percentage or absolute amount to the calculated quantities required for a job
This additional allowance is called overs
Overs are allowed for in the Layout screen and in the Materials screen.
The formula is [base overs] + [calculated quantity] + ([calculated quantity] * [percentage overs]
The same fields are found in the layout screen. Within a job the precedence is:
If overs are specified in a material, then this over-rides overs found overs in the layout section