"...Offset values in PVI labels should be visible when the option is enabled, but they are not. Nothing shows up at all..."
When using Civil 3D alignments, the definition must be accessible inside the profile production reference drawing. This enables offset calculation capability for ASE, using the Civil 3D alignment.
Additional Info - Stationing
Alignments defined as shortcuts in the profile drawing don't need to be visible, nor do they require labels. Only the definition is needed.
ASE's Paving data does not include offsets for each key point. Offsets are not present in the paving data file because ASE can calculate them in real-time, based on user-defined conditions.
For example, the Profile Generator preferences can be configured so some PVI labels will show offsets and others could be suppressed, based on their locations; or maybe no PVI's will show offsets; or maybe they'll ALL show offsets? This can't be anticipated by ASE.
Why Not Just Include Offsets in the Paving Data?
Offsets are not automatically calculated for each key point because it would increase processing time unnecessarily. Creating and managing offsets is impractical because it's possible that the information may not ever be needed at all. So ASE calculates offsets "on-demand" to speed things up during design & production.
Why Can ASE Alignments Show Paving Offsets So Easily?
When you connect to an ASE project containing alignments, those definitions are immediately loaded as "Read-Only" references on initialization. Offsets can then be calculated for any alignment on the project.
This is not the case with Civil 3D alignments. To calculate an offset, the Civil 3D alignment definition must first be loaded manually via data shortcut.