When creating drawings in Imperial the width of the plate is in Metric. To resolve this issue, follow the procedure below
1. Select “Management Tools” button in the upper right corner on the Home tab.
2. Select the Defaults category
3. Use the filter and type plate
4. Change the Plate name to [20,5006,474] from [3,3,1].
Remove the "x%Length after width if you want the length removed from the INTERNAL Structured BOM list Description.
Remember to “Load Settings in Advance."
Go back to the model and Update Defaults.