Working range is the pressure and depth a given area accepts on a given day.
It changes with sleep, stress, load, and last session. In 📝Deep Tissue Massage the practitioner finds that range rather than importing yesterday's. Forcing past it causes guarding; staying inside it is how depth is actually reached. Working range is a dose finding, not a diagnosis of how tight someone is as a trait, and not a score of the practitioner.
Clients feel the difference as a pass they can stay with versus a pass they brace against. The number on the 📝pressure scale is one way to name it; the breath is another.