You might be right with 20 mill - I guess it depends on who you commission and how fancy your building is.
I have a quote on my desk for a EASA certified level D for 8mill sterling installed with the rider that all the usual procedures are in place for it to be certified by CAA.
There is real competition n the market now and CAE are slowly losing dominance

You don't indicate aircraft type, but +/- USD 11M is the market price for many aircraft types., irrespective of manufacturer

I also assume the quote is for an FFS built in accordance with CS-FSTD A because TDMs can't qualify FSTDs, only operators can.

So not far off then? $20mill is having someone's' leg over.
The quote included the cost of it being certified by the operator - all part of their sales pitch I gather.
As this is a rotary thread so didn't think I'd have to include 'H' 😉