Re: Xrandr reports wrong refresh rate
No. The problem is that the NVIDIA driver has to make each metamode look unique to the X server. With DynamicTwinview enabled, you could add a metamode that clones two monitors with the exact same size and refresh rate as the single-display metamode. To the X server, these would appear as the same mode. The driver has to make the modes look unique, and the refresh rate field is the only way to do it.
You can query the actual refresh rates of the display devices in a metamode through the NV-CONTROL extension.