I selected 4 decimal places in settings for unit pricing but I can only use 2 places on an item. What's happening?
In order to use Precision Pricing and increase the available decimal places to 3 or 4, take the following steps:
1) Quick Menu → Settings → General tab - Set the number of decimals available to 3 or 4.
2) On the items for which you need to have more than 2 decimals, open the Item detail card and click the Setup tab. Increase the decimal setting to 3 or 4.
From what is being described, you have taken the first step but not the second.