Fixed offset slider vs. host system timezone for stable regional time display in After Effects

When a project must render a text layer showing a specific regional time that remains consistent across workstations, the documented options create a trade-off between portability and maintenance. One approach relies on the expression language’s Date object and the host system’s locale, optionally attempting to pass an IANA identifier to toLocaleString. Another approach stores a fixed UTC offset in a slider control and applies it manually, avoiding dependence on the host timezone.

The uncertainty is that After Effects does not ship an IANA timezone database, and older versions reportedly ignore the timeZone option in expression date formatting, falling back to the host locale. ExtendScript can read the operating system timezone via environment variables or getTimezoneOffset(), but those values reflect the host machine and cannot be overridden per project without external libraries. The fixed-offset method avoids cross-machine drift but requires manual updates when daylight-saving rules change.

Assuming the documented behavior still applies to current releases, which approach is appropriate for a project that must display a fixed regional time on both Windows and macOS without shifting when opened on a machine in a different timezone? Does any current version of After Effects respect the timeZone argument in expressions, or is the slider-based offset still the only reliable documented method? If the timeZone option is supported, what is the earliest version where it consistently honors an IANA identifier rather than falling back to the host locale?