That's about 500 series size (3U x 1.5"). I think for two metal anodized and milled panels I paid about $70.
That seems about right. The thing with Schaeffer is the more holes and text you put on the panel the higher the cost. With an aluminium PCB it makes no difference.
If you need quantity, say 25+ pieces, then also consider full metal panels with powder coat and silkscreen. Could be cost competitive with aluminum PCB.
At that quantity I think you are right because the fixed tooling charges become a smaller proportion of the unit panel cost. And of course they look much nicer. I have never needed that many so far simply because customers usually want something unique and the quantities are not sufficient to justify it.
Cheers
Ian