The Materials tab in the Design module provides additional information on the amount of materials consumed per crate and the entire Unit ( total crates in the design equals a unit)

The only value that changes in this tab when the quantity of crates is changed, is the Unit Quantity

All other values will show a single crate calculation and will not change based on the number of crates in the design. Users can multiply these values by the quantity of crates in this design / unit,  or can click on the export icon and view a spreadsheet with single and design/ unit totals.

An example using materials calculated by Sheet:

The Unit Quantity values are not to be used as a "shopping list". An example is the 'Sheet' quantity for panelboard and foam. Based on the required dimensions of the pieces in your design and the dimensions of the purchased material, the actual Unit Quantity may be higher or lower. 

The Unit Quantity value is a direct calculation from the 'Plus Waste' amount multiplied by the Quantity of crates.

Commonly companies set a default Waste % so that over time and/or many designs, the total number of sheets equals out.  This provides a better ROI (return on investment) as the typical amount of time to determine the actual waste % per design tends to cost more in labor costs, than setting the values to average out over time. The Waste % can be modified as needed for designs that are outside the norms and might skew your typical settings.

However, companies that do a small amount of crate orders, may be better served to set the waste % on a design by design basis. 

Users wishing to charge customers for 'FULL SHEET' pricing can add the different in Design > Packing > Other: the selecting the Plywood category and the material to be added. In the example above, lets say you want to charge for 4 sheets. 

4 - 1.979 = 2.021   This value is added in the QTY field in Packing> Other to account for a total of 4 sheets. 

Please also review this more technical article as to why Crate Pro provides this result: Crate Pro & Yield Optimization

As a common industry tribal info:

Ordering extra sheets of plywood will allow for project waste and scrap pieces that can’t be used.