The cues on the tape are evenly distributed from -5 to 5v. This means that as you add more cue points, the range of voltages that correspond to a given cue point decrease. Also, cue points that you add are not simply added to the end of the range, but rather inserted into the range exactly between whatever two cue points are on either side of the new cue on the tape. So to summarize, the mapping of cue points to -5 to 5v respects the order of cue points as they appear on the tape, but not their distance from each other on the tape because they are now evenly distributed in the -5 to 5v range. Since I was working with just a few cue points on the tape, the voltage ranges corresponding to a given cue point were quite wide, so it was easy to seek a certain cue point.
With lots of cue points on a tape, I like to think of the Nav functionality as a way to discover unexpected and ephemeral sequences of tape loops, rather than a way of strictly composing a predefined sequence.