Just had an interesting conversation via the Chat route.
The latest "definitive" answer for the "when will I see the credit" question indicates three months, that 3-billing cycles, application of the credit automatically. I changed over the Note in early October so was "assured" the credit would be applied to the January bill. I didn't specifically ask about the return and that processing as to which date was being used but the feeling I got was that the return wasn't the trigger point for the processing to start. Will see in January I guess.
Dbeak mentioned the S7 Edge promotion for $15/month so I snuck that question into the chat. The rep indicated, after I pressed the issue a bit, that Edge 7 owners would get the promo fee applied, again, in a separate transaction from the Samsung credit, to start in 3 months time and that it would occur "automatically." Rather than charging $15/month, they would credit the bill, over the 24 months, to reflect a $492.00 savings...by my calculator , that would take $20.00 per month off the bill rather than charge just $15.00 for the equipment payment. Seems convoluted but am guessing taxes may play in there somewhere.
Still, will see how far that one goes.