The purpose of this enhancement is to restrict users from viewing the cost column on labor line items on Service Orders.
Prior to V18.0, all users with permission "View Invoice Sensitive Data" had access to the Cost column for all line items (labor, parts, sublet, etc.) by clicking CTRL+H:
After V18.0, the Cost column on labor lines will now be restricted. Only users with the permission to "View Service Order Labor Cost" will see a cost value for the labor lines:
For those users who do not have this permission, the Cost column will still display for all other line items (parts), but on the labor line items, the cost will show up blank.