An interesting change to the oranized book was pointed out on reddit recently. Probably originally cross posted from here but it is germane to this conversation so i'll cross post back.
The new version adds the following:
The Governing Body does not impose its conscience on the worldwide congregation as to how time spent in field service is to be counted, nor has anyone else been appointed to make a judgment in this matter.
It also deletes the following which was in the 2005 book:
There are essential activities for which time is not counted, such as ... traveling to and from the territory.