Does the manual say what the range is supposed to be? I've never seen a receiver with a scale from -99 to +1; it's usually -something to +10 or so.
However, be aware that the volume trims for each channel affect the range. Let's say the range is -99 to +10, but one or more of the channel trims is at +9 - then the total range would now be -99 to +1.