In the Design module > Details > Materials, there is a 'Unit Quantity value for each of the materials used in the design. The 'Unit Quantity; should never be used as a 'shopping list' for a design. 

The values in the 'Unit Quantity' field and the 'Plus Waste' field are equal values, except they may be displayed in different units of measure. 

The unit of measure in the 'Plus Waste' field will be the same as Level A in the Inventory module.

The unit of measure in the 'Unit Quantity' field will be based on the selected Tracking Level for that item in the Inventory. (Tracking Level is the unit of measure you prefer for entering your purchasing cost)

If your 'Waste Factor' is accurate for the material, users will find that over a period of time (30 to 90 days is common), when you run a report for total usage of your materials, the total 'Unit Quantity' tends to be an accurate representation of the average usage of that material. 
This allows companies to evaluate their usage of particular materials and order them appropriately.

For some designs, you may be aware that using the default values for the waste factor, will skew your average costs / selling price and total usage. These are situations where its beneficial to go to  Details > Materials and adjust the 'Waste Factor' % for that material in that design. (changes in a design will not affect your default Preferences)

Examples are:

  • The dimensions are such that you need just over 1/2 of a sheet for each crate panel, so your actual waste % will be excessively high. Adjusting the waste % here would increase what you would charge for this  job and better average out your material usage. 
  • Your able to utilize materials that normally would have been counted as part of your waste %. This significantly lowers the actual waste % in this design.  Manually adjusting here would lower your costs and selling price. The benefit could be that this helps you get the job in a price point market and will better average out your material usage.
  • You do a small volume of crates so that the calculated waste average doesn't have enough data to provide a representation of actual usage. Quickly adjusting the waste % would give you a better representation of usage.

Generally, adjusting the waste factor % in every design, tends to increase your costs in labor time in excess of what additional profit you might gain by more exact material usage. While in some situations, adjusting the waste % for each design, does make sense, for the majority of custom crating companies, there is a better ROI, to use with the averages.

For materials that are calculated 'By Sheet' or 'By Roll', you will find the same issue.