Having the 990 stay muted when changing inputs has been a welcome change for me. Tonygeno is absolutely right that keeping mute on while changing volume is not included on the 990, but as you say it's been done the "standard" way for so long (by which I mean that changing volume un-mutes) that most people would probably be confused if it didn't work that way - inertia is a powerful thing, probably approaching too powerful to grant much room for change in this case. The reasoning that I've always assumed for this behavior (which has been present on every component I've owned that had a mute button, as far as I can recall, which may be why I have this rationale in my head) was that volume control encompassed both the up/down controls and the mute control, such that if I asked for the volume to be changed it was assumed that I also wanted to hear it. But who knows, maybe the Model 995 will prove me wrong and include the "MeanGene mute."