Scenecapture2d poor performance in vr packaged game

In relation to UE-59090 which involves poor packaged performance of Ocvulus VR applications that utilize SceneCapture2D functionality, I have improved the performance of my Packaged application greatly by setting r.SceneRenderTargetResizeMethod to 2, but am still seeing roughly half the frame rate of the VR Preview. The issue is considered solved by Epic, but I am still not totally satisfied. After all, this worked well under 4.18. In the editor, using dynamic rescaling, my game stays at 100% resolution, perhaps dropping to 94%. In Packaged game, it drops to 50% which was unacceptable.