So to sumup:
1. Pref - Audio - Audio Driver Bit Depth is grayed out when using ASIO if interface only allows one setting for ASIO.
2. Transport screen displays Pref - File - Audio Data - Record Bit Depth setting for any new recorded audio.
3. Interface may follow Sonar's setting and may not depending on the interface.
4. Frozen tracks will contain FX if set to do so by rightclicking the Freeze button.
 
What is the Transport screen actually displaying for Bit Rate and how is it changed?

the transport now show 48/24, after I have change it

Good stuff, I've been following. Today I've been getting to know my new Scarlett 18i20 2nd gen today and one goal was to ensure sample rates and bit depths were consistent in the chain without hunting all screens.
I have SPLAT on new laptop now, Windows 10. Always desktops until now and firewire FA-101interface. Been using Producer, X1, etc for maybe (7?) years

Thanks!