That is correct. VR will make the image appear less sharp when mounted on a tripod. Since after all, there's not a lot of vibration to reduce. (Unless you have a shatty tripod)
That's pretty much the best idea, with "most" of the Nikon VR lenses. When the tripod head is locked down, you want VR off...if the head is loosey-goosey, and you are just using the tripod to control the weight of the camera, I think VR can and should be left ON, with most lenses, at least if the shutter speeds are slow or slowish. I do not have any of the VERY-newest high-end Nikkors with the VERY-newest VR system, which I believe, can be used on a tripod with good results, even with the head locked tightly.
I also recommend that you go into the menu and turn exposure delay ON. That will pop the mirror up when you press the shutter but delay the exposure for a couple of seconds to allow the tripod vibrations to dissipate. Using a wireless remote is also recommend when using a tripod to further reduce vibrations.