Like Vulcan said, the WMR setting of auto will ignore the steamVR reprojection setting. If you really want to lock your frame rate to 45fps and use reprojection either set WMR to "Motion Vector", which will force it on for everything, or set WMR to "SteamVr per-app setting" and then set DCS's steamVR video settings to "Force Always-On". Using Auto will allow your frame rates to bounce around and it will only use reprojection when it needs it. If you want to see this in action, enable the reprojection status indicator in the developer tab of the WMR settings. It's a handy little tool.