I'm trying to turn the chime volume way down in the Settings panel for it, and the allowable range of values for it is limited to something like 25-35. I can't turn it down to anything less than 25 (the full bar is shown, but everything to the left of 25 and to the right of 35 is greyed out/inactive and unavailable). Why would they show a full range of 0-100 but only allow adjustment within a very narrow range of volumes?