How to update a picking sequence

The picking sequence is a bin location that determines what items populate inventory workbooks for a cycle count or inventory physical. The objective is to isolate items in the same physical area to a single count sheet. An example of a picking sequence is RACK18-C.

I want to update my picking sequences through the item setup. The item setup has a field listed as 'Default Picking Sequence'. I've made changes to several items and ran the inventory workbook to ensure the changes took effect with an updated picking sequence. However, the changes did not take effect and still reflect the old picking sequences prior to my manual update. Am I omitting a step? How do I update a picking sequence in Sage 300?