When editing the Unit of Measure in Method, it stops syncing correctly.

Unfortunately, the QuickBooks SDK (the tools QuickBooks gives us to interact with it) doesn't correctly handle changes to the UOM. In some situations, when you edit a UOM, QuickBooks will actually archive the original UOM and create a brand new UOM, assigning a new ID in backend. This makes it difficult, and in some cases impossible, for 3rd party apps, like Method, to accurately reflect these changes correctly within their applications.

For more information on the ramifications of changing the UOM, you can read this article on Insightful Account, "Changing QuickBooks Units of Measure – No, No, No!"

For each UOM, there should be completely separate items.

Intuit recommends not to change the UOM. Instead, Intuit recommends you create an entirely new UOM set with the different base unit, and for items with the old UOM, you should create new items with a new UOM.

For example, let's take the scenario of selling soda pop. Instead of creating one item "Soda Pop" and using UOM to define the quantity of units, create six items and designate the unit as a "Case":

If you're looking to show the unit of Measure on a transaction screen or a report, we recommend using a Linked Field.

Linked fields restrict the ability to change unit of measure, maintaining data integrity.