1) Custom sounds - that's always the case when you change the sound file.
2) Did you press BACK instead of CLEAR to reset the timer? The BACK button on the main screen has been access to the volume control as long as we've had volume control.
3) The spirits know because the read the PDF
4) The voltage, like RPM, is filtered and therefore the display does not show instantaneous change; however, the alarms are based on the immediate value received from the device. Always been this way, always will be.
5) You can turn off the Rx Voltage report by going into the screen and turning it off there.
The problem I thought you were trying to solve was that you weren't getting an alarm when the voltage is low. That's what CLEAR on the Min/Max screen is the workaround for. Next version has it corrected, as noted earlier. If you don't have a receiver giving you telemetry data, IT CANT'T ALARM! This is because of (4) above. The alarms are generated as telemetry is received. No telemetry, no alarm.
Andy