Thinking about convergence, it occurs to me that I'm not really sure how AH reports ranges.
Here's my question: when AH changes the range from 400 to 200, does it mean:
that the range has just crossed from 201 to 200, or
does it mean that the range has moved from 300 to 299 ( ie the range is rounded to the nearest reported value, of the set 200, 400, 600, 800.... )?
The answer would have an obvious impact on trying to use convergence to its maximum effect.