I think in this case it is down to the DSU version used and manufacturer preference. Known DSU versions so far are 1.3, 1.6, 1.7 & 1.8. 1.3 allowed DV with anything, 1.6 tied it to Dolby Surround Night mode for many brands (Denon/Marantz did not offer this as they have their own volume tech). Of...