Advanced Preferences - Thresholds - Customer Freight

I have set up the preference (Advanced Preference Type 14 - Customer Freight) with Quantity Level Break turned on, and set up a few examples. When setting up the details, you can then set up a From Level and the Threshold UM. The issue that I am having is that if I set up a Threshold UM of 'LB', it seems to work properly, the Freight Handling Code is assigned per the preference. Unfortunately, we'd like to be able to drive the selection at a piece level. All items are set with a Primary UOM of 'EA', and if I