Hi jcl,
The manual states that:
True Range (TR); max(High,Close)-min(Low,Close) of the current asset price series. See also ATR, ATRS.
I always understood the above formula as simply the range, the true range tries to incorporate opening gaps by comparing to the previous close.
Should the formula not be max(high[0],close[1]) - min(low[0],close[-1]) ?
If it is, then the manual needs to be updated to reflect this on the true range and ATRS entries.