I wonder whether the R44 may be a rather atypical helicopter, with a low RoD in autorotation.
I haven't flown one for many years, but recall that although the limitations section include a max DA of 14,000ft, there is another "altitude" limitation of 9,000ft agl "as the aircraft would otherwise take more than 5 minutes to land in the event of a fire". I suspect this implies a low RoD (rather than a rapid escalation of a fire in this type). I cannot recall a similar limitation in other types.