Scenario
User wants to hide both the Average Cost and Purchase Price, but there is no separate Permission for both Average Cost and Purchase Price
Solution
Create a Custom Form:
1. Navigate to Customization > Forms > Transaction Forms
2. Click Edit on your preferred Sales Order Form
3. Provide a new name for the form on the Name field
4. Under the Screenfield tab uncheck the Show checkbox for Average Cost and Purchase Price.
5. Mouse hover to the down arrow beside the Save button and select Save As.
To Restrict the Form to a Role:
1. Navigate to Setup > Users/Roles > Manage Roles.
2. Click Edit for the role in concern that you want to update.
3. Under Forms > Transaction subtab, put a checkmark on the Preferred checkbox for the created Custom Form created above.
4. Put a checkmark on the Restricted checkbox for the same form.
5. Click Save.