I've only worked on a couple V6s, and it was to update software on both. As I recall, the OEM software would zero the calibration value when you entered that mode, so you had to start from scratch each time, which is why it was a good idea to write the value down afterwards. One of the updated software versions could correctly read the saved calibration value from rig memory, but could not save a new value, although I think that was fixed in later versions. The software I liked is referred to as "Reed's software" and it corrected the OEM CW offset issue and did calibrations correctly.
=Vic=
Vic WA4THR