You are right on all points. The Status Change message is sent in the blind to no specific device address so no ACK or retry. A Group Cleanup Direct command is sent to each device that has been linked to the Input, with ACK and message retry. With a good powerline network, Status Change should be reliable, but I would recommend using a link and the Group commands that go with it if you have that option.
Reply To: Need additional documentation on INSTEON commands 2017-12-21T19:48:12+00:00