Hi Jim,
(sorry for delay - was away on my day-job for several days...)
There is a general quest to make things as intuitive as possible so if you have any ideas about how the interface can work better let me know!
The setting up for a reverse measurement is slightly quirky at the moment as you need to reset the distance, erase the old waypoints and then select the reverse reset option - all of which is straight forward but not necessarily a slick process. (The calibration resets to the 'pre' calibration constant which may go unnoticed too...).
It is technically possible to flip-flop between forward and reverse measurements AFTER the measurement has taken place (ie multiple forward/reverse resets) with the reference point counter values being recalculated to their equivalent 'virtual' inverse readings. The data points are retained (properly positioned) but beware that if the finish point is then moved the reference points will drift off - the reversing process assumes a fixed datum point but if that datum is moved between reversals then the subsequent reversal may not yield the original distances for the reference points. This would be a convoluted thing to do but I only mention it to emphasise the nature and implication of the 'reset'.
Let me know how you get on with it - I've only tested this on paper with an artificial set of data from a mirror-image of a forward measurement.
There is also a glaring omission in that multiple runs can't be saved - no big technical issue but the next update will have a scheme for archiving past measurements so that, for example, several measurements of a course can be stored.
I've just seen a release note that iOS6 is available for developers so another problem as my iPod won't be compatible (must be time for a new one...) Also the maps function is changing away from GoogleMaps to [I believe] TomTom which may be seamless or may not be. I'm still formulating a plan for the proximity alarm to operate on the location functions.
Feedback welcome as always!
Dougie