This is the most US small "l" liberal thing I've ever seen

The Government didn't change the location necessarily, rather, when the line was built there were provisions for an additional 4 stations (Truganina, Davis Road, Sayers Road, and Black Forest Road). To date the state government has only committed to and funded the first two, not the latter.

I personally can't recall any provisional date being suggested by Government, nor for the Black Forest Road station

There's provisions in the regional rail link design (when the line was built) and in the planning overlay for two stations between Tarneit and Wyndham Vale. The second will eventually get built, the question is when.

This is so helpful, thank you!